UI based on AbstractBasicComponentContainer (#2924)

Change-Id: I1614a3464b8e7a0e9ecdd8c3a76335cdb85bdf87

55 files changed, 907 insertions, 523 deletions

diff --git a/client/src/com/vaadin/client/ui/ui/UIConnector.java b/client/src/com/vaadin/client/ui/ui/UIConnector.java
index c1083a2bb4..a0898b3281 100644
--- a/client/src/com/vaadin/client/ui/ui/UIConnector.java
+++ b/client/src/com/vaadin/client/ui/ui/UIConnector.java
@@ -337,11 +337,19 @@ public class UIConnector extends AbstractComponentContainerConnector implements
     }
 
     protected ComponentConnector getContent() {
-        return (ComponentConnector) getState().content;
+        List<ComponentConnector> children = getChildComponents();
+        if (children.isEmpty()) {
+            return null;
+        } else {
+            return children.get(0);
+        }
     }
 
     protected void onChildSizeChange() {
         ComponentConnector child = getContent();
+        if (child == null) {
+            return;
+        }
         Style childStyle = child.getWidget().getElement().getStyle();
         /*
          * Must set absolute position if the child has relative height and
@@ -408,12 +416,16 @@ public class UIConnector extends AbstractComponentContainerConnector implements
                 childStateChangeHandlerRegistration.removeHandler();
                 childStateChangeHandlerRegistration = null;
             }
-            getWidget().setWidget(newChild.getWidget());
-            childStateChangeHandlerRegistration = newChild
-                    .addStateChangeHandler(childStateChangeHandler);
-            // Must handle new child here as state change events are already
-            // fired
-            onChildSizeChange();
+            if (newChild != null) {
+                getWidget().setWidget(newChild.getWidget());
+                childStateChangeHandlerRegistration = newChild
+                        .addStateChangeHandler(childStateChangeHandler);
+                // Must handle new child here as state change events are already
+                // fired
+                onChildSizeChange();
+            } else {
+                getWidget().setWidget(null);
+            }
         }
 
         for (ComponentConnector c : getChildComponents()) {
diff --git a/server/src/com/vaadin/ui/AbstractComponentContainer.java b/server/src/com/vaadin/ui/AbstractComponentContainer.java
index fdc753b57c..c60f312293 100644
--- a/server/src/com/vaadin/ui/AbstractComponentContainer.java
+++ b/server/src/com/vaadin/ui/AbstractComponentContainer.java
@@ -16,7 +16,6 @@
 
 package com.vaadin.ui;
 
-import java.lang.reflect.Method;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -83,32 +82,11 @@ public abstract class AbstractComponentContainer extends AbstractComponent
         }
     }
 
-    /* Events */
-
-    private static final Method COMPONENT_ATTACHED_METHOD;
-
-    private static final Method COMPONENT_DETACHED_METHOD;
-
-    static {
-        try {
-            COMPONENT_ATTACHED_METHOD = ComponentAttachListener.class
-                    .getDeclaredMethod("componentAttachedToContainer",
-                            new Class[] { ComponentAttachEvent.class });
-            COMPONENT_DETACHED_METHOD = ComponentDetachListener.class
-                    .getDeclaredMethod("componentDetachedFromContainer",
-                            new Class[] { ComponentDetachEvent.class });
-        } catch (final java.lang.NoSuchMethodException e) {
-            // This should never happen
-            throw new java.lang.RuntimeException(
-                    "Internal error finding methods in AbstractComponentContainer");
-        }
-    }
-
     /* documented in interface */
     @Override
     public void addComponentAttachListener(ComponentAttachListener listener) {
-        addListener(ComponentContainer.ComponentAttachEvent.class, listener,
-                COMPONENT_ATTACHED_METHOD);
+        addListener(ComponentAttachEvent.class, listener,
+                ComponentAttachListener.attachMethod);
     }
 
     /**
@@ -123,9 +101,9 @@ public abstract class AbstractComponentContainer extends AbstractComponent
 
     /* documented in interface */
     @Override
-    public void addComponentDetachListener(ComponentDetachListener listener) {
-        addListener(ComponentContainer.ComponentDetachEvent.class, listener,
-                COMPONENT_DETACHED_METHOD);
+    public void removeComponentAttachListener(ComponentAttachListener listener) {
+        removeListener(ComponentAttachEvent.class, listener,
+                ComponentAttachListener.attachMethod);
     }
 
     /**
@@ -140,9 +118,9 @@ public abstract class AbstractComponentContainer extends AbstractComponent
 
     /* documented in interface */
     @Override
-    public void removeComponentAttachListener(ComponentAttachListener listener) {
-        removeListener(ComponentContainer.ComponentAttachEvent.class, listener,
-                COMPONENT_ATTACHED_METHOD);
+    public void addComponentDetachListener(ComponentDetachListener listener) {
+        addListener(ComponentDetachEvent.class, listener,
+                ComponentDetachListener.detachMethod);
     }
 
     /**
@@ -158,8 +136,8 @@ public abstract class AbstractComponentContainer extends AbstractComponent
     /* documented in interface */
     @Override
     public void removeComponentDetachListener(ComponentDetachListener listener) {
-        removeListener(ComponentContainer.ComponentDetachEvent.class, listener,
-                COMPONENT_DETACHED_METHOD);
+        removeListener(ComponentDetachEvent.class, listener,
+                ComponentDetachListener.detachMethod);
     }
 
     /**
@@ -218,9 +196,7 @@ public abstract class AbstractComponentContainer extends AbstractComponent
 
         if (c.getParent() != null) {
             // If the component already has a parent, try to remove it
-            ComponentContainer oldParent = (ComponentContainer) c.getParent();
-            oldParent.removeComponent(c);
-
+            AbstractSingleComponentContainer.removeFromParent(c);
         }
 
         c.setParent(this);
@@ -250,7 +226,7 @@ public abstract class AbstractComponentContainer extends AbstractComponent
 
         super.setVisible(visible);
         // If the visibility state is toggled it might affect all children
-        // aswell, e.g. make container visible should make children visible if
+        // as well, e.g. make container visible should make children visible if
         // they were only hidden because the container was hidden.
         markAsDirtyRecursive();
     }
@@ -315,30 +291,15 @@ public abstract class AbstractComponentContainer extends AbstractComponent
 
     private Collection<Component> getInvalidSizedChildren(final boolean vertical) {
         HashSet<Component> components = null;
-        if (this instanceof Panel) {
-            Panel p = (Panel) this;
-            ComponentContainer content = p.getContent();
+        for (Component component : this) {
             boolean valid = vertical ? ComponentSizeValidator
-                    .checkHeights(content) : ComponentSizeValidator
-                    .checkWidths(content);
-
+                    .checkHeights(component) : ComponentSizeValidator
+                    .checkWidths(component);
             if (!valid) {
-                components = new HashSet<Component>(1);
-                components.add(content);
-            }
-        } else {
-            for (Iterator<Component> componentIterator = getComponentIterator(); componentIterator
-                    .hasNext();) {
-                Component component = componentIterator.next();
-                boolean valid = vertical ? ComponentSizeValidator
-                        .checkHeights(component) : ComponentSizeValidator
-                        .checkWidths(component);
-                if (!valid) {
-                    if (components == null) {
-                        components = new HashSet<Component>();
-                    }
-                    components.add(component);
+                if (components == null) {
+                    components = new HashSet<Component>();
                 }
+                components.add(component);
             }
         }
         return components;
diff --git a/server/src/com/vaadin/ui/AbstractSingleComponentContainer.java b/server/src/com/vaadin/ui/AbstractSingleComponentContainer.java
new file mode 100644
index 0000000000..20660ce955
--- /dev/null
+++ b/server/src/com/vaadin/ui/AbstractSingleComponentContainer.java
@@ -0,0 +1,281 @@
+/*
+ * Copyright 2011-2012 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.ui;
+
+import java.util.Collections;
+import java.util.Iterator;
+
+import com.vaadin.server.ComponentSizeValidator;
+
+/**
+ * Abstract base class for component containers that have only one child
+ * component.
+ * 
+ * For component containers that support multiple children, inherit
+ * {@link AbstractComponentContainer} instead of this class.
+ * 
+ * @since 7.0
+ */
+public abstract class AbstractSingleComponentContainer extends
+        AbstractComponent implements SingleComponentContainer {
+
+    private Component content;
+
+    @Override
+    public int getComponentCount() {
+        return (content != null) ? 1 : 0;
+    }
+
+    @Override
+    public Iterator<Component> iterator() {
+        if (content != null) {
+            return Collections.singletonList(content).iterator();
+        } else {
+            return Collections.<Component> emptyList().iterator();
+        }
+    }
+
+    /* documented in interface */
+    @Override
+    public void addComponentAttachListener(ComponentAttachListener listener) {
+        addListener(ComponentAttachEvent.class, listener,
+                ComponentAttachListener.attachMethod);
+
+    }
+
+    /* documented in interface */
+    @Override
+    public void removeComponentAttachListener(ComponentAttachListener listener) {
+        removeListener(ComponentAttachEvent.class, listener,
+                ComponentAttachListener.attachMethod);
+    }
+
+    /* documented in interface */
+    @Override
+    public void addComponentDetachListener(ComponentDetachListener listener) {
+        addListener(ComponentDetachEvent.class, listener,
+                ComponentDetachListener.detachMethod);
+    }
+
+    /* documented in interface */
+    @Override
+    public void removeComponentDetachListener(ComponentDetachListener listener) {
+        removeListener(ComponentDetachEvent.class, listener,
+                ComponentDetachListener.detachMethod);
+    }
+
+    /**
+     * Fires the component attached event. This is called by the
+     * {@link #setContent(Component)} method after the component has been set as
+     * the content.
+     * 
+     * @param component
+     *            the component that has been added to this container.
+     */
+    protected void fireComponentAttachEvent(Component component) {
+        fireEvent(new ComponentAttachEvent(this, component));
+    }
+
+    /**
+     * Fires the component detached event. This is called by the
+     * {@link #setContent(Component)} method after the content component has
+     * been replaced by other content.
+     * 
+     * @param component
+     *            the component that has been removed from this container.
+     */
+    protected void fireComponentDetachEvent(Component component) {
+        fireEvent(new ComponentDetachEvent(this, component));
+    }
+
+    /*
+     * (non-Javadoc)
+     * 
+     * @see
+     * com.vaadin.ui.HasComponents#isComponentVisible(com.vaadin.ui.Component)
+     */
+    @Override
+    public boolean isComponentVisible(Component childComponent) {
+        return true;
+    }
+
+    @Override
+    public void setVisible(boolean visible) {
+        if (isVisible() == visible) {
+            return;
+        }
+
+        super.setVisible(visible);
+        // If the visibility state is toggled it might affect all children
+        // aswell, e.g. make container visible should make children visible if
+        // they were only hidden because the container was hidden.
+        markAsDirtyRecursive();
+    }
+
+    @Override
+    public Component getContent() {
+        return content;
+    }
+
+    /**
+     * Sets the content of this container. The content is a component that
+     * serves as the outermost item of the visual contents.
+     * 
+     * The content must always be set, either with a constructor parameter or by
+     * calling this method.
+     * 
+     * Previous versions of Vaadin used a {@link VerticalLayout} with margins
+     * enabled as the default content but that is no longer the case.
+     * 
+     * @param content
+     *            a component (typically a layout) to use as content
+     */
+    @Override
+    public void setContent(Component content) {
+        Component oldContent = getContent();
+        if (oldContent == content) {
+            // do not set the same content twice
+            return;
+        }
+        if (oldContent != null && oldContent.getParent() == this) {
+            oldContent.setParent(null);
+            fireComponentDetachEvent(oldContent);
+        }
+        this.content = content;
+        if (content != null) {
+            removeFromParent(content);
+
+            content.setParent(this);
+            fireComponentAttachEvent(content);
+        }
+
+        markAsDirty();
+    }
+
+    /**
+     * Utility method for removing a component from its parent (if possible).
+     * 
+     * @param content
+     *            component to remove
+     */
+    // TODO move utility method elsewhere?
+    public static void removeFromParent(Component content)
+            throws IllegalArgumentException {
+        HasComponents parent = content.getParent();
+        if (parent instanceof ComponentContainer) {
+            // If the component already has a parent, try to remove it
+            ComponentContainer oldParent = (ComponentContainer) parent;
+            oldParent.removeComponent(content);
+        } else if (parent instanceof SingleComponentContainer) {
+            SingleComponentContainer oldParent = (SingleComponentContainer) parent;
+            if (oldParent.getContent() == content) {
+                oldParent.setContent(null);
+            }
+        } else if (parent != null) {
+            throw new IllegalArgumentException(
+                    "Content is already attached to another parent");
+        }
+    }
+
+    // the setHeight()/setWidth() methods duplicated and simplified from
+    // AbstractComponentContainer
+
+    @Override
+    public void setWidth(float width, Unit unit) {
+        /*
+         * child tree repaints may be needed, due to our fall back support for
+         * invalid relative sizes
+         */
+        boolean dirtyChild = false;
+        boolean childrenMayBecomeUndefined = false;
+        if (getWidth() == SIZE_UNDEFINED && width != SIZE_UNDEFINED) {
+            // children currently in invalid state may need repaint
+            dirtyChild = getInvalidSizedChild(false);
+        } else if ((width == SIZE_UNDEFINED && getWidth() != SIZE_UNDEFINED)
+                || (unit == Unit.PERCENTAGE
+                        && getWidthUnits() != Unit.PERCENTAGE && !ComponentSizeValidator
+                            .parentCanDefineWidth(this))) {
+            /*
+             * relative width children may get to invalid state if width becomes
+             * invalid. Width may also become invalid if units become percentage
+             * due to the fallback support
+             */
+            childrenMayBecomeUndefined = true;
+            dirtyChild = getInvalidSizedChild(false);
+        }
+        super.setWidth(width, unit);
+        repaintChangedChildTree(dirtyChild, childrenMayBecomeUndefined, false);
+    }
+
+    private void repaintChangedChildTree(boolean invalidChild,
+            boolean childrenMayBecomeUndefined, boolean vertical) {
+        if (getContent() == null) {
+            return;
+        }
+        boolean needRepaint = false;
+        if (childrenMayBecomeUndefined) {
+            // if became invalid now
+            needRepaint = !invalidChild && getInvalidSizedChild(vertical);
+        } else if (invalidChild) {
+            // if not still invalid
+            needRepaint = !getInvalidSizedChild(vertical);
+        }
+        if (needRepaint) {
+            getContent().markAsDirtyRecursive();
+        }
+    }
+
+    private boolean getInvalidSizedChild(final boolean vertical) {
+        Component content = getContent();
+        if (content == null) {
+            return false;
+        }
+        if (vertical) {
+            return !ComponentSizeValidator.checkHeights(content);
+        } else {
+            return !ComponentSizeValidator.checkWidths(content);
+        }
+    }
+
+    @Override
+    public void setHeight(float height, Unit unit) {
+        /*
+         * child tree repaints may be needed, due to our fall back support for
+         * invalid relative sizes
+         */
+        boolean dirtyChild = false;
+        boolean childrenMayBecomeUndefined = false;
+        if (getHeight() == SIZE_UNDEFINED && height != SIZE_UNDEFINED) {
+            // children currently in invalid state may need repaint
+            dirtyChild = getInvalidSizedChild(true);
+        } else if ((height == SIZE_UNDEFINED && getHeight() != SIZE_UNDEFINED)
+                || (unit == Unit.PERCENTAGE
+                        && getHeightUnits() != Unit.PERCENTAGE && !ComponentSizeValidator
+                            .parentCanDefineHeight(this))) {
+            /*
+             * relative height children may get to invalid state if height
+             * becomes invalid. Height may also become invalid if units become
+             * percentage due to the fallback support.
+             */
+            childrenMayBecomeUndefined = true;
+            dirtyChild = getInvalidSizedChild(true);
+        }
+        super.setHeight(height, unit);
+        repaintChangedChildTree(dirtyChild, childrenMayBecomeUndefined, true);
+    }
+
+}
diff --git a/server/src/com/vaadin/ui/ComponentContainer.java b/server/src/com/vaadin/ui/ComponentContainer.java
index 3663134520..5ef41d7cbf 100644
--- a/server/src/com/vaadin/ui/ComponentContainer.java
+++ b/server/src/com/vaadin/ui/ComponentContainer.java
@@ -16,9 +16,10 @@
 
 package com.vaadin.ui;
 
-import java.io.Serializable;
 import java.util.Iterator;
 
+import com.vaadin.ui.HasComponents.ComponentAttachDetachNotifier;
+
 /**
  * Extension to the {@link Component} interface which adds to it the capacity to
  * contain other components. All UI elements that can have child elements
@@ -27,7 +28,8 @@ import java.util.Iterator;
  * @author Vaadin Ltd.
  * @since 3.0
  */
-public interface ComponentContainer extends HasComponents {
+public interface ComponentContainer extends HasComponents,
+        ComponentAttachDetachNotifier {
 
     /**
      * Adds the component into this container.
@@ -102,14 +104,6 @@ public interface ComponentContainer extends HasComponents {
     public void moveComponentsFrom(ComponentContainer source);
 
     /**
-     * Listens the component attach events.
-     * 
-     * @param listener
-     *            the listener to add.
-     */
-    public void addComponentAttachListener(ComponentAttachListener listener);
-
-    /**
      * @deprecated Since 7.0, replaced by
      *             {@link #addComponentAttachListener(ComponentAttachListener)}
      **/
@@ -117,14 +111,6 @@ public interface ComponentContainer extends HasComponents {
     public void addListener(ComponentAttachListener listener);
 
     /**
-     * Stops the listening component attach events.
-     * 
-     * @param listener
-     *            the listener to removed.
-     */
-    public void removeComponentAttachListener(ComponentAttachListener listener);
-
-    /**
      * @deprecated Since 7.0, replaced by
      *             {@link #removeComponentAttachListener(ComponentAttachListener)}
      **/
@@ -132,11 +118,6 @@ public interface ComponentContainer extends HasComponents {
     public void removeListener(ComponentAttachListener listener);
 
     /**
-     * Listens the component detach events.
-     */
-    public void addComponentDetachListener(ComponentDetachListener listener);
-
-    /**
      * @deprecated Since 7.0, replaced by
      *             {@link #addComponentDetachListener(ComponentDetachListener)}
      **/
@@ -144,130 +125,10 @@ public interface ComponentContainer extends HasComponents {
     public void addListener(ComponentDetachListener listener);
 
     /**
-     * Stops the listening component detach events.
-     */
-    public void removeComponentDetachListener(ComponentDetachListener listener);
-
-    /**
      * @deprecated Since 7.0, replaced by
      *             {@link #removeComponentDetachListener(ComponentDetachListener)}
      **/
     @Deprecated
     public void removeListener(ComponentDetachListener listener);
 
-    /**
-     * Component attach listener interface.
-     */
-    public interface ComponentAttachListener extends Serializable {
-
-        /**
-         * A new component is attached to container.
-         * 
-         * @param event
-         *            the component attach event.
-         */
-        public void componentAttachedToContainer(ComponentAttachEvent event);
-    }
-
-    /**
-     * Component detach listener interface.
-     */
-    public interface ComponentDetachListener extends Serializable {
-
-        /**
-         * A component has been detached from container.
-         * 
-         * @param event
-         *            the component detach event.
-         */
-        public void componentDetachedFromContainer(ComponentDetachEvent event);
-    }
-
-    /**
-     * Component attach event sent when a component is attached to container.
-     */
-    @SuppressWarnings("serial")
-    public static class ComponentAttachEvent extends Component.Event {
-
-        private final Component component;
-
-        /**
-         * Creates a new attach event.
-         * 
-         * @param container
-         *            the component container the component has been detached
-         *            to.
-         * @param attachedComponent
-         *            the component that has been attached.
-         */
-        public ComponentAttachEvent(ComponentContainer container,
-                Component attachedComponent) {
-            super(container);
-            component = attachedComponent;
-        }
-
-        /**
-         * Gets the component container.
-         * 
-         * @param the
-         *            component container.
-         */
-        public ComponentContainer getContainer() {
-            return (ComponentContainer) getSource();
-        }
-
-        /**
-         * Gets the attached component.
-         * 
-         * @param the
-         *            attach component.
-         */
-        public Component getAttachedComponent() {
-            return component;
-        }
-    }
-
-    /**
-     * Component detach event sent when a component is detached from container.
-     */
-    @SuppressWarnings("serial")
-    public static class ComponentDetachEvent extends Component.Event {
-
-        private final Component component;
-
-        /**
-         * Creates a new detach event.
-         * 
-         * @param container
-         *            the component container the component has been detached
-         *            from.
-         * @param detachedComponent
-         *            the component that has been detached.
-         */
-        public ComponentDetachEvent(ComponentContainer container,
-                Component detachedComponent) {
-            super(container);
-            component = detachedComponent;
-        }
-
-        /**
-         * Gets the component container.
-         * 
-         * @param the
-         *            component container.
-         */
-        public ComponentContainer getContainer() {
-            return (ComponentContainer) getSource();
-        }
-
-        /**
-         * Gets the detached component.
-         * 
-         * @return the detached component.
-         */
-        public Component getDetachedComponent() {
-            return component;
-        }
-    }
-
 }
diff --git a/server/src/com/vaadin/ui/HasComponents.java b/server/src/com/vaadin/ui/HasComponents.java
index db0aa1ca8e..4f6320f6b2 100644
--- a/server/src/com/vaadin/ui/HasComponents.java
+++ b/server/src/com/vaadin/ui/HasComponents.java
@@ -15,8 +15,12 @@
  */
 package com.vaadin.ui;
 
+import java.io.Serializable;
+import java.lang.reflect.Method;
 import java.util.Iterator;
 
+import com.vaadin.util.ReflectTools;
+
 /**
  * Interface that must be implemented by all {@link Component}s that contain
  * other {@link Component}s.
@@ -55,4 +59,161 @@ public interface HasComponents extends Component, Iterable<Component> {
      */
     public boolean isComponentVisible(Component childComponent);
 
+    /**
+     * Interface for {@link HasComponents} implementations that support sending
+     * attach and detach events for components.
+     * 
+     * @since 7.0
+     */
+    public interface ComponentAttachDetachNotifier extends Serializable {
+        /**
+         * Listens the component attach events.
+         * 
+         * @param listener
+         *            the listener to add.
+         */
+        public void addComponentAttachListener(ComponentAttachListener listener);
+
+        /**
+         * Stops the listening component attach events.
+         * 
+         * @param listener
+         *            the listener to removed.
+         */
+        public void removeComponentAttachListener(
+                ComponentAttachListener listener);
+
+        /**
+         * Listens the component detach events.
+         */
+        public void addComponentDetachListener(ComponentDetachListener listener);
+
+        /**
+         * Stops the listening component detach events.
+         */
+        public void removeComponentDetachListener(
+                ComponentDetachListener listener);
+    }
+
+    /**
+     * Component attach listener interface.
+     */
+    public interface ComponentAttachListener extends Serializable {
+
+        public static final Method attachMethod = ReflectTools.findMethod(
+                ComponentAttachListener.class, "componentAttachedToContainer",
+                ComponentAttachEvent.class);
+
+        /**
+         * A new component is attached to container.
+         * 
+         * @param event
+         *            the component attach event.
+         */
+        public void componentAttachedToContainer(ComponentAttachEvent event);
+    }
+
+    /**
+     * Component detach listener interface.
+     */
+    public interface ComponentDetachListener extends Serializable {
+
+        public static final Method detachMethod = ReflectTools.findMethod(
+                ComponentDetachListener.class,
+                "componentDetachedFromContainer", ComponentDetachEvent.class);
+
+        /**
+         * A component has been detached from container.
+         * 
+         * @param event
+         *            the component detach event.
+         */
+        public void componentDetachedFromContainer(ComponentDetachEvent event);
+    }
+
+    /**
+     * Component attach event sent when a component is attached to container.
+     */
+    @SuppressWarnings("serial")
+    public static class ComponentAttachEvent extends Component.Event {
+
+        private final Component component;
+
+        /**
+         * Creates a new attach event.
+         * 
+         * @param container
+         *            the container the component has been detached to.
+         * @param attachedComponent
+         *            the component that has been attached.
+         */
+        public ComponentAttachEvent(HasComponents container,
+                Component attachedComponent) {
+            super(container);
+            component = attachedComponent;
+        }
+
+        /**
+         * Gets the component container.
+         * 
+         * @param the
+         *            component container.
+         */
+        public HasComponents getContainer() {
+            return (HasComponents) getSource();
+        }
+
+        /**
+         * Gets the attached component.
+         * 
+         * @param the
+         *            attach component.
+         */
+        public Component getAttachedComponent() {
+            return component;
+        }
+    }
+
+    /**
+     * Component detach event sent when a component is detached from container.
+     */
+    @SuppressWarnings("serial")
+    public static class ComponentDetachEvent extends Component.Event {
+
+        private final Component component;
+
+        /**
+         * Creates a new detach event.
+         * 
+         * @param container
+         *            the container the component has been detached from.
+         * @param detachedComponent
+         *            the component that has been detached.
+         */
+        public ComponentDetachEvent(HasComponents container,
+                Component detachedComponent) {
+            super(container);
+            component = detachedComponent;
+        }
+
+        /**
+         * Gets the component container.
+         * 
+         * @param the
+         *            component container.
+         */
+        public HasComponents getContainer() {
+            return (HasComponents) getSource();
+        }
+
+        /**
+         * Gets the detached component.
+         * 
+         * @return the detached component.
+         */
+        public Component getDetachedComponent() {
+            return component;
+        }
+    }
+
 }
diff --git a/server/src/com/vaadin/ui/LegacyWindow.java b/server/src/com/vaadin/ui/LegacyWindow.java
index 88559af0b5..79d4d0aedb 100644
--- a/server/src/com/vaadin/ui/LegacyWindow.java
+++ b/server/src/com/vaadin/ui/LegacyWindow.java
@@ -1,6 +1,6 @@
 /*
 @VaadinApache2LicenseForJavaFiles@
-*/
+ */
 
 package com.vaadin.ui;
 
@@ -9,16 +9,16 @@ import java.net.URL;
 
 import com.vaadin.server.LegacyApplication;
 import com.vaadin.server.Page;
-import com.vaadin.server.Resource;
-import com.vaadin.server.VaadinRequest;
 import com.vaadin.server.Page.BrowserWindowResizeEvent;
 import com.vaadin.server.Page.BrowserWindowResizeListener;
+import com.vaadin.server.Resource;
+import com.vaadin.server.VaadinRequest;
 import com.vaadin.shared.ui.BorderStyle;
 
 /**
- * Helper class to emulate the main window from Vaadin 6 using UIs. This
- * class should be used in the same way as Window used as a browser level
- * window in Vaadin 6 with {@link com.vaadin.server.LegacyApplication}
+ * Helper class to emulate the main window from Vaadin 6 using UIs. This class
+ * should be used in the same way as Window used as a browser level window in
+ * Vaadin 6 with {@link com.vaadin.server.LegacyApplication}
  */
 @Deprecated
 public class LegacyWindow extends UI {
@@ -29,7 +29,8 @@ public class LegacyWindow extends UI {
      * Create a new legacy window
      */
     public LegacyWindow() {
-        super();
+        super(new VerticalLayout());
+        ((VerticalLayout) getContent()).setMargin(true);
     }
 
     /**
@@ -39,7 +40,8 @@ public class LegacyWindow extends UI {
      *            the caption of the window
      */
     public LegacyWindow(String caption) {
-        super();
+        super(new VerticalLayout());
+        ((VerticalLayout) getContent()).setMargin(true);
         setCaption(caption);
     }
 
@@ -71,12 +73,11 @@ public class LegacyWindow extends UI {
      * Gets the unique name of the window. The name of the window is used to
      * uniquely identify it.
      * <p>
-     * The name also determines the URL that can be used for direct access
-     * to a window. All windows can be accessed through
-     * {@code http://host:port/app/win} where {@code http://host:port/app}
-     * is the application URL (as returned by
-     * {@link LegacyApplication#getURL()} and {@code win} is the window
-     * name.
+     * The name also determines the URL that can be used for direct access to a
+     * window. All windows can be accessed through
+     * {@code http://host:port/app/win} where {@code http://host:port/app} is
+     * the application URL (as returned by {@link LegacyApplication#getURL()}
+     * and {@code win} is the window name.
      * </p>
      * <p>
      * Note! Portlets do not support direct window access through URLs.
@@ -92,12 +93,11 @@ public class LegacyWindow extends UI {
      * Sets the unique name of the window. The name of the window is used to
      * uniquely identify it inside the application.
      * <p>
-     * The name also determines the URL that can be used for direct access
-     * to a window. All windows can be accessed through
-     * {@code http://host:port/app/win} where {@code http://host:port/app}
-     * is the application URL (as returned by
-     * {@link LegacyApplication#getURL()} and {@code win} is the window
-     * name.
+     * The name also determines the URL that can be used for direct access to a
+     * window. All windows can be accessed through
+     * {@code http://host:port/app/win} where {@code http://host:port/app} is
+     * the application URL (as returned by {@link LegacyApplication#getURL()}
+     * and {@code win} is the window name.
      * </p>
      * <p>
      * This method can only be called before the window is added to an
@@ -107,8 +107,8 @@ public class LegacyWindow extends UI {
      * </p>
      * 
      * @param name
-     *            the new name for the window or null if the application
-     *            should automatically assign a name to it
+     *            the new name for the window or null if the application should
+     *            automatically assign a name to it
      * @throws IllegalStateException
      *             if the window is attached to an application
      */
@@ -124,14 +124,14 @@ public class LegacyWindow extends UI {
     }
 
     /**
-     * Gets the full URL of the window. The returned URL is window specific
-     * and can be used to directly refer to the window.
+     * Gets the full URL of the window. The returned URL is window specific and
+     * can be used to directly refer to the window.
      * <p>
      * Note! This method can not be used for portlets.
      * </p>
      * 
-     * @return the URL of the window or null if the window is not attached
-     *         to an application
+     * @return the URL of the window or null if the window is not attached to an
+     *         application
      */
     public URL getURL() {
         LegacyApplication application = getApplication();
@@ -148,8 +148,8 @@ public class LegacyWindow extends UI {
     }
 
     /**
-     * Opens the given resource in this UI. The contents of this UI is
-     * replaced by the {@code Resource}.
+     * Opens the given resource in this UI. The contents of this UI is replaced
+     * by the {@code Resource}.
      * 
      * @param resource
      *            the resource to show in this UI
@@ -167,41 +167,39 @@ public class LegacyWindow extends UI {
      * Opens the given resource in a window with the given name.
      * <p>
      * The supplied {@code windowName} is used as the target name in a
-     * window.open call in the client. This means that special values such
-     * as "_blank", "_self", "_top", "_parent" have special meaning. An
-     * empty or <code>null</code> window name is also a special case.
+     * window.open call in the client. This means that special values such as
+     * "_blank", "_self", "_top", "_parent" have special meaning. An empty or
+     * <code>null</code> window name is also a special case.
      * </p>
      * <p>
-     * "", null and "_self" as {@code windowName} all causes the resource to
-     * be opened in the current window, replacing any old contents. For
+     * "", null and "_self" as {@code windowName} all causes the resource to be
+     * opened in the current window, replacing any old contents. For
      * downloadable content you should avoid "_self" as "_self" causes the
      * client to skip rendering of any other changes as it considers them
-     * irrelevant (the page will be replaced by the resource). This can
-     * speed up the opening of a resource, but it might also put the client
-     * side into an inconsistent state if the window content is not
-     * completely replaced e.g., if the resource is downloaded instead of
-     * displayed in the browser.
+     * irrelevant (the page will be replaced by the resource). This can speed up
+     * the opening of a resource, but it might also put the client side into an
+     * inconsistent state if the window content is not completely replaced e.g.,
+     * if the resource is downloaded instead of displayed in the browser.
      * </p>
      * <p>
-     * "_blank" as {@code windowName} causes the resource to always be
-     * opened in a new window or tab (depends on the browser and browser
-     * settings).
+     * "_blank" as {@code windowName} causes the resource to always be opened in
+     * a new window or tab (depends on the browser and browser settings).
      * </p>
      * <p>
-     * "_top" and "_parent" as {@code windowName} works as specified by the
-     * HTML standard.
+     * "_top" and "_parent" as {@code windowName} works as specified by the HTML
+     * standard.
      * </p>
      * <p>
-     * Any other {@code windowName} will open the resource in a window with
-     * that name, either by opening a new window/tab in the browser or by
-     * replacing the contents of an existing window with that name.
+     * Any other {@code windowName} will open the resource in a window with that
+     * name, either by opening a new window/tab in the browser or by replacing
+     * the contents of an existing window with that name.
      * </p>
      * <p>
-     * As of Vaadin 7.0.0, the functionality for opening a Resource in a
-     * Page has been replaced with similar methods based on a String URL.
-     * This is because the usage of Resource is problematic with memory
-     * management and with security features in some browsers. Is is
-     * recommended to instead use {@link Link} for starting downloads.
+     * As of Vaadin 7.0.0, the functionality for opening a Resource in a Page
+     * has been replaced with similar methods based on a String URL. This is
+     * because the usage of Resource is problematic with memory management and
+     * with security features in some browsers. Is is recommended to instead use
+     * {@link Link} for starting downloads.
      * </p>
      * 
      * @param resource
@@ -220,11 +218,11 @@ public class LegacyWindow extends UI {
      * name. For more information on the meaning of {@code windowName}, see
      * {@link #open(Resource, String)}.
      * <p>
-     * As of Vaadin 7.0.0, the functionality for opening a Resource in a
-     * Page has been replaced with similar methods based on a String URL.
-     * This is because the usage of Resource is problematic with memory
-     * management and with security features in some browsers. Is is
-     * recommended to instead use {@link Link} for starting downloads.
+     * As of Vaadin 7.0.0, the functionality for opening a Resource in a Page
+     * has been replaced with similar methods based on a String URL. This is
+     * because the usage of Resource is problematic with memory management and
+     * with security features in some browsers. Is is recommended to instead use
+     * {@link Link} for starting downloads.
      * </p>
      * 
      * @param resource
@@ -246,9 +244,9 @@ public class LegacyWindow extends UI {
     }
 
     /**
-     * Adds a new {@link BrowserWindowResizeListener} to this UI. The
-     * listener will be notified whenever the browser window within which
-     * this UI resides is resized.
+     * Adds a new {@link BrowserWindowResizeListener} to this UI. The listener
+     * will be notified whenever the browser window within which this UI resides
+     * is resized.
      * 
      * @param resizeListener
      *            the listener to add
@@ -264,9 +262,8 @@ public class LegacyWindow extends UI {
     }
 
     /**
-     * Removes a {@link BrowserWindowResizeListener} from this UI. The
-     * listener will no longer be notified when the browser window is
-     * resized.
+     * Removes a {@link BrowserWindowResizeListener} from this UI. The listener
+     * will no longer be notified when the browser window is resized.
      * 
      * @param resizeListener
      *            the listener to remove
@@ -290,8 +287,7 @@ public class LegacyWindow extends UI {
     }
 
     /**
-     * Gets the last known width of the browser window in which this UI
-     * resides.
+     * Gets the last known width of the browser window in which this UI resides.
      * 
      * @return the browser window width in pixels
      * 
@@ -306,18 +302,17 @@ public class LegacyWindow extends UI {
      * Executes JavaScript in this window.
      * 
      * <p>
-     * This method allows one to inject javascript from the server to
-     * client. A client implementation is not required to implement this
-     * functionality, but currently all web-based clients do implement this.
+     * This method allows one to inject javascript from the server to client. A
+     * client implementation is not required to implement this functionality,
+     * but currently all web-based clients do implement this.
      * </p>
      * 
      * <p>
-     * Executing javascript this way often leads to cross-browser
-     * compatibility issues and regressions that are hard to resolve. Use of
-     * this method should be avoided and instead it is recommended to create
-     * new widgets with GWT. For more info on creating own, reusable
-     * client-side widgets in Java, read the corresponding chapter in Book
-     * of Vaadin.
+     * Executing javascript this way often leads to cross-browser compatibility
+     * issues and regressions that are hard to resolve. Use of this method
+     * should be avoided and instead it is recommended to create new widgets
+     * with GWT. For more info on creating own, reusable client-side widgets in
+     * Java, read the corresponding chapter in Book of Vaadin.
      * </p>
      * 
      * @param script
@@ -338,4 +333,77 @@ public class LegacyWindow extends UI {
         getPage().setTitle(caption);
     }
 
+    @Override
+    public ComponentContainer getContent() {
+        return (ComponentContainer) super.getContent();
+    }
+
+    /**
+     * Set the content of the window. For a {@link LegacyWindow}, the content
+     * must be a {@link ComponentContainer}.
+     * 
+     * @param content
+     */
+    @Override
+    public void setContent(Component content) {
+        if (!(content instanceof ComponentContainer)) {
+            throw new IllegalArgumentException(
+                    "The content of a LegacyWindow must be a ComponentContainer");
+        }
+        super.setContent(content);
+    }
+
+    /**
+     * This implementation replaces a component in the content container (
+     * {@link #getContent()}) instead of in the actual UI.
+     * 
+     * This method should only be called when the content is a
+     * {@link ComponentContainer} (default {@link VerticalLayout} or explicitly
+     * set).
+     */
+    public void replaceComponent(Component oldComponent, Component newComponent) {
+        getContent().replaceComponent(oldComponent, newComponent);
+    }
+
+    /**
+     * Adds a component to this UI. The component is not added directly to the
+     * UI, but instead to the content container ({@link #getContent()}).
+     * 
+     * This method should only be called when the content is a
+     * {@link ComponentContainer} (default {@link VerticalLayout} or explicitly
+     * set).
+     * 
+     * @param component
+     *            the component to add to this UI
+     * 
+     * @see #getContent()
+     */
+    public void addComponent(Component component) {
+        getContent().addComponent(component);
+    }
+
+    /**
+     * This implementation removes the component from the content container (
+     * {@link #getContent()}) instead of from the actual UI.
+     * 
+     * This method should only be called when the content is a
+     * {@link ComponentContainer} (default {@link VerticalLayout} or explicitly
+     * set).
+     */
+    public void removeComponent(Component component) {
+        getContent().removeComponent(component);
+    }
+
+    /**
+     * This implementation removes the components from the content container (
+     * {@link #getContent()}) instead of from the actual UI.
+     * 
+     * This method should only be called when the content is a
+     * {@link ComponentContainer} (default {@link VerticalLayout} or explicitly
+     * set).
+     */
+    public void removeAllComponents() {
+        getContent().removeAllComponents();
+    }
+
 }
\ No newline at end of file
diff --git a/server/src/com/vaadin/ui/SingleComponentContainer.java b/server/src/com/vaadin/ui/SingleComponentContainer.java
new file mode 100644
index 0000000000..deb647e5eb
--- /dev/null
+++ b/server/src/com/vaadin/ui/SingleComponentContainer.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2012 Vaadin Ltd.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package com.vaadin.ui;
+
+import com.vaadin.ui.HasComponents.ComponentAttachDetachNotifier;
+
+/**
+ * Interface for component containers that have one child component and do not
+ * support adding or removing components.
+ * 
+ * For component containers that support multiple children, see
+ * {@link ComponentContainer} instead.
+ * 
+ * @since 7.0
+ */
+public interface SingleComponentContainer extends HasComponents,
+        ComponentAttachDetachNotifier {
+
+    /**
+     * Gets the number of children this {@link SingleComponentContainer} has.
+     * This must be symmetric with what {@link #iterator()} returns and thus
+     * typically return 1 if the content is set, 0 otherwise.
+     * 
+     * @return The number of child components this container has.
+     */
+    public int getComponentCount();
+
+    /**
+     * Gets the content of this container. The content is a component that
+     * serves as the outermost item of the visual contents.
+     * 
+     * @return a component to use as content
+     * 
+     * @see #setContent(Component)
+     */
+    public Component getContent();
+
+    /**
+     * Sets the content of this container. The content is a component that
+     * serves as the outermost item of the visual contents.
+     * 
+     * The content should always be set, either as a constructor parameter or by
+     * calling this method.
+     * 
+     * @return a component (typically a layout) to use as content
+     */
+    public void setContent(Component content);
+
+}
diff --git a/server/src/com/vaadin/ui/UI.java b/server/src/com/vaadin/ui/UI.java
index d2f323e5fe..e4cee9386a 100644
--- a/server/src/com/vaadin/ui/UI.java
+++ b/server/src/com/vaadin/ui/UI.java
@@ -69,9 +69,9 @@ import com.vaadin.util.ReflectTools;
  * After a UI has been created by the application, it is initialized using
  * {@link #init(VaadinRequest)}. This method is intended to be overridden by the
  * developer to add components to the user interface and initialize
- * non-component functionality. The component hierarchy is initialized by
- * passing a {@link ComponentContainer} with the main layout of the view to
- * {@link #setContent(ComponentContainer)}.
+ * non-component functionality. The component hierarchy must be initialized by
+ * passing a {@link Component} with the main layout or other content of the view
+ * to {@link #setContent(Component)} or to the constructor of the UI.
  * </p>
  * 
  * @see #init(VaadinRequest)
@@ -79,7 +79,7 @@ import com.vaadin.util.ReflectTools;
  * 
  * @since 7.0
  */
-public abstract class UI extends AbstractComponentContainer implements
+public abstract class UI extends AbstractSingleComponentContainer implements
         Action.Container, Action.Notifier, LegacyComponent {
 
     /**
@@ -178,22 +178,23 @@ public abstract class UI extends AbstractComponentContainer implements
     private long lastUidlRequest = System.currentTimeMillis();
 
     /**
-     * Creates a new empty UI without a caption. This UI will have a
-     * {@link VerticalLayout} with margins enabled as its content.
+     * Creates a new empty UI without a caption. The content of the UI must be
+     * set by calling {@link #setContent(Component)} before using the UI.
      */
     public UI() {
-        this((ComponentContainer) null);
+        this(null);
     }
 
     /**
-     * Creates a new UI with the given component container as its content.
+     * Creates a new UI with the given component (often a layout) as its
+     * content.
      * 
      * @param content
-     *            the content container to use as this UIs content.
+     *            the component to use as this UIs content.
      * 
-     * @see #setContent(ComponentContainer)
+     * @see #setContent(Component)
      */
-    public UI(ComponentContainer content) {
+    public UI(Component content) {
         registerRpc(rpc);
         setSizeFull();
         setContent(content);
@@ -224,15 +225,6 @@ public abstract class UI extends AbstractComponentContainer implements
     }
 
     /**
-     * This implementation replaces a component in the content container (
-     * {@link #getContent()}) instead of in the actual UI.
-     */
-    @Override
-    public void replaceComponent(Component oldComponent, Component newComponent) {
-        getContent().replaceComponent(oldComponent, newComponent);
-    }
-
-    /**
      * Gets the application object to which the component is attached.
      * 
      * <p>
@@ -330,7 +322,7 @@ public abstract class UI extends AbstractComponentContainer implements
     /*
      * (non-Javadoc)
      * 
-     * @see com.vaadin.ui.ComponentContainer#getComponentIterator()
+     * @see com.vaadin.ui.HasComponents#iterator()
      */
     @Override
     public Iterator<Component> iterator() {
@@ -541,89 +533,6 @@ public abstract class UI extends AbstractComponentContainer implements
     }
 
     /**
-     * Gets the content of this UI. The content is a component container that
-     * serves as the outermost item of the visual contents of this UI.
-     * 
-     * @return a component container to use as content
-     * 
-     * @see #setContent(ComponentContainer)
-     * @see #createDefaultLayout()
-     */
-    public ComponentContainer getContent() {
-        return (ComponentContainer) getState().content;
-    }
-
-    /**
-     * Helper method to create the default content layout that is used if no
-     * content has not been explicitly defined.
-     * 
-     * @return a newly created layout
-     */
-    private static VerticalLayout createDefaultLayout() {
-        VerticalLayout layout = new VerticalLayout();
-        layout.setMargin(true);
-        return layout;
-    }
-
-    /**
-     * Sets the content of this UI. The content is a component container that
-     * serves as the outermost item of the visual contents of this UI. If no
-     * content has been set, a {@link VerticalLayout} with margins enabled will
-     * be used by default - see {@link #createDefaultLayout()}. The content can
-     * also be set in a constructor.
-     * 
-     * @return a component container to use as content
-     * 
-     * @see #UI(ComponentContainer)
-     * @see #createDefaultLayout()
-     */
-    public void setContent(ComponentContainer content) {
-        if (content == null) {
-            content = createDefaultLayout();
-        }
-
-        if (getState().content != null) {
-            super.removeComponent((Component) getState().content);
-        }
-        getState().content = content;
-        if (content != null) {
-            super.addComponent(content);
-        }
-    }
-
-    /**
-     * Adds a component to this UI. The component is not added directly to the
-     * UI, but instead to the content container ({@link #getContent()}).
-     * 
-     * @param component
-     *            the component to add to this UI
-     * 
-     * @see #getContent()
-     */
-    @Override
-    public void addComponent(Component component) {
-        getContent().addComponent(component);
-    }
-
-    /**
-     * This implementation removes the component from the content container (
-     * {@link #getContent()}) instead of from the actual UI.
-     */
-    @Override
-    public void removeComponent(Component component) {
-        getContent().removeComponent(component);
-    }
-
-    /**
-     * This implementation removes the components from the content container (
-     * {@link #getContent()}) instead of from the actual UI.
-     */
-    @Override
-    public void removeAllComponents() {
-        getContent().removeAllComponents();
-    }
-
-    /**
      * Internal initialization method, should not be overridden. This method is
      * not declared as final because that would break compatibility with e.g.
      * CDI.
diff --git a/server/tests/src/com/vaadin/tests/server/component/abstractcomponentcontainer/TestAbstractComponentContainerListeners.java b/server/tests/src/com/vaadin/tests/server/component/abstractcomponentcontainer/TestAbstractComponentContainerListeners.java
index f9f170eb2a..9763354b57 100644
--- a/server/tests/src/com/vaadin/tests/server/component/abstractcomponentcontainer/TestAbstractComponentContainerListeners.java
+++ b/server/tests/src/com/vaadin/tests/server/component/abstractcomponentcontainer/TestAbstractComponentContainerListeners.java
@@ -1,10 +1,10 @@
 package com.vaadin.tests.server.component.abstractcomponentcontainer;
 
 import com.vaadin.tests.server.component.AbstractListenerMethodsTest;
-import com.vaadin.ui.ComponentContainer.ComponentAttachEvent;
-import com.vaadin.ui.ComponentContainer.ComponentAttachListener;
-import com.vaadin.ui.ComponentContainer.ComponentDetachEvent;
-import com.vaadin.ui.ComponentContainer.ComponentDetachListener;
+import com.vaadin.ui.HasComponents.ComponentAttachEvent;
+import com.vaadin.ui.HasComponents.ComponentAttachListener;
+import com.vaadin.ui.HasComponents.ComponentDetachEvent;
+import com.vaadin.ui.HasComponents.ComponentDetachListener;
 import com.vaadin.ui.HorizontalLayout;
 import com.vaadin.ui.VerticalLayout;
 
diff --git a/server/tests/src/com/vaadin/tests/server/component/ui/UIAddRemoveComponents.java b/server/tests/src/com/vaadin/tests/server/component/ui/LegacyUIAddRemoveComponents.java
index 1b07321605..1a5e19e0da 100644
--- a/server/tests/src/com/vaadin/tests/server/component/ui/UIAddRemoveComponents.java
+++ b/server/tests/src/com/vaadin/tests/server/component/ui/LegacyUIAddRemoveComponents.java
@@ -9,11 +9,11 @@ import org.junit.Test;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.ui.Component;
 import com.vaadin.ui.Label;
-import com.vaadin.ui.UI;
+import com.vaadin.ui.LegacyWindow;
 
-public class UIAddRemoveComponents {
+public class LegacyUIAddRemoveComponents {
 
-    private static class TestUI extends UI {
+    private static class TestUI extends LegacyWindow {
         @Override
         protected void init(VaadinRequest request) {
         }
@@ -21,7 +21,7 @@ public class UIAddRemoveComponents {
 
     @Test
     public void addComponent() {
-        UI ui = new TestUI();
+        TestUI ui = new TestUI();
         Component c = new Label("abc");
 
         ui.addComponent(c);
@@ -34,7 +34,7 @@ public class UIAddRemoveComponents {
 
     @Test
     public void removeComponent() {
-        UI ui = new TestUI();
+        TestUI ui = new TestUI();
         Component c = new Label("abc");
 
         ui.addComponent(c);
@@ -49,7 +49,7 @@ public class UIAddRemoveComponents {
 
     @Test
     public void replaceComponent() {
-        UI ui = new TestUI();
+        TestUI ui = new TestUI();
         Component c = new Label("abc");
         Component d = new Label("def");
 
diff --git a/server/tests/src/com/vaadin/tests/server/components/ComponentAttachDetachListenerTest.java b/server/tests/src/com/vaadin/tests/server/components/ComponentAttachDetachListenerTest.java
index 3ba1c4c7f1..df515795eb 100644
--- a/server/tests/src/com/vaadin/tests/server/components/ComponentAttachDetachListenerTest.java
+++ b/server/tests/src/com/vaadin/tests/server/components/ComponentAttachDetachListenerTest.java
@@ -8,14 +8,14 @@ import com.vaadin.ui.AbsoluteLayout;
 import com.vaadin.ui.AbsoluteLayout.ComponentPosition;
 import com.vaadin.ui.AbstractOrderedLayout;
 import com.vaadin.ui.Component;
-import com.vaadin.ui.ComponentContainer;
-import com.vaadin.ui.ComponentContainer.ComponentAttachEvent;
-import com.vaadin.ui.ComponentContainer.ComponentAttachListener;
-import com.vaadin.ui.ComponentContainer.ComponentDetachEvent;
-import com.vaadin.ui.ComponentContainer.ComponentDetachListener;
 import com.vaadin.ui.CssLayout;
 import com.vaadin.ui.GridLayout;
 import com.vaadin.ui.GridLayout.Area;
+import com.vaadin.ui.HasComponents;
+import com.vaadin.ui.HasComponents.ComponentAttachEvent;
+import com.vaadin.ui.HasComponents.ComponentAttachListener;
+import com.vaadin.ui.HasComponents.ComponentDetachEvent;
+import com.vaadin.ui.HasComponents.ComponentDetachListener;
 import com.vaadin.ui.HorizontalLayout;
 import com.vaadin.ui.Label;
 
@@ -29,12 +29,12 @@ public class ComponentAttachDetachListenerTest extends TestCase {
     // General variables
     private int attachCounter = 0;
     private Component attachedComponent = null;
-    private ComponentContainer attachTarget = null;
+    private HasComponents attachTarget = null;
     private boolean foundInContainer = false;
 
     private int detachCounter = 0;
     private Component detachedComponent = null;
-    private ComponentContainer detachedTarget = null;
+    private HasComponents detachedTarget = null;
 
     // Ordered layout specific variables
     private int indexOfComponent = -1;
@@ -53,7 +53,7 @@ public class ComponentAttachDetachListenerTest extends TestCase {
             attachTarget = event.getContainer();
 
             // Search for component in container (should be found)
-            Iterator<Component> iter = attachTarget.getComponentIterator();
+            Iterator<Component> iter = attachTarget.iterator();
             while (iter.hasNext()) {
                 if (iter.next() == attachedComponent) {
                     foundInContainer = true;
@@ -83,7 +83,7 @@ public class ComponentAttachDetachListenerTest extends TestCase {
             detachedTarget = event.getContainer();
 
             // Search for component in container (should NOT be found)
-            Iterator<Component> iter = detachedTarget.getComponentIterator();
+            Iterator<Component> iter = detachedTarget.iterator();
             while (iter.hasNext()) {
                 if (iter.next() == detachedComponent) {
                     foundInContainer = true;
@@ -129,20 +129,20 @@ public class ComponentAttachDetachListenerTest extends TestCase {
         super.setUp();
 
         olayout = new HorizontalLayout();
-        olayout.addListener(new MyAttachListener());
-        olayout.addListener(new MyDetachListener());
+        olayout.addComponentAttachListener(new MyAttachListener());
+        olayout.addComponentDetachListener(new MyDetachListener());
 
         gridlayout = new GridLayout();
-        gridlayout.addListener(new MyAttachListener());
-        gridlayout.addListener(new MyDetachListener());
+        gridlayout.addComponentAttachListener(new MyAttachListener());
+        gridlayout.addComponentDetachListener(new MyDetachListener());
 
         absolutelayout = new AbsoluteLayout();
-        absolutelayout.addListener(new MyAttachListener());
-        absolutelayout.addListener(new MyDetachListener());
+        absolutelayout.addComponentAttachListener(new MyAttachListener());
+        absolutelayout.addComponentDetachListener(new MyDetachListener());
 
         csslayout = new CssLayout();
-        csslayout.addListener(new MyAttachListener());
-        csslayout.addListener(new MyDetachListener());
+        csslayout.addComponentAttachListener(new MyAttachListener());
+        csslayout.addComponentDetachListener(new MyDetachListener());
     }
 
     public void testOrderedLayoutAttachListener() {
diff --git a/server/tests/src/com/vaadin/ui/LabelDataSource.java b/server/tests/src/com/vaadin/ui/LabelDataSource.java
index 506a635814..7ef8d67c2a 100644
--- a/server/tests/src/com/vaadin/ui/LabelDataSource.java
+++ b/server/tests/src/com/vaadin/ui/LabelDataSource.java
@@ -122,7 +122,7 @@ public class LabelDataSource {
         label.setPropertyDataSource(integerDataSource);
         UI ui = new MockUI();
         ui.setLocale(Locale.GERMANY);
-        ui.addComponent(label);
+        ui.setContent(label);
         Assert.assertEquals(INTEGER_STRING_VALUE_DE, label.getState().text);
     }
 }
diff --git a/shared/src/com/vaadin/shared/ui/ui/UIState.java b/shared/src/com/vaadin/shared/ui/ui/UIState.java
index 6bbfeb18e1..c734ee5d0b 100644
--- a/shared/src/com/vaadin/shared/ui/ui/UIState.java
+++ b/shared/src/com/vaadin/shared/ui/ui/UIState.java
@@ -16,8 +16,6 @@
 package com.vaadin.shared.ui.ui;
 
 import com.vaadin.shared.ComponentState;
-import com.vaadin.shared.Connector;
 
 public class UIState extends ComponentState {
-    public Connector content;
 }
\ No newline at end of file
diff --git a/uitest/src/com/vaadin/tests/Components.java b/uitest/src/com/vaadin/tests/Components.java
index de408104ae..7f024e774a 100644
--- a/uitest/src/com/vaadin/tests/Components.java
+++ b/uitest/src/com/vaadin/tests/Components.java
@@ -22,7 +22,6 @@ import com.vaadin.shared.ui.label.ContentMode;
 import com.vaadin.tests.components.AbstractComponentTest;
 import com.vaadin.ui.AbstractComponent;
 import com.vaadin.ui.Component;
-import com.vaadin.ui.ComponentContainer;
 import com.vaadin.ui.Embedded;
 import com.vaadin.ui.HorizontalSplitPanel;
 import com.vaadin.ui.Label;
@@ -256,7 +255,7 @@ public class Components extends LegacyApplication {
         try {
             AbstractComponentTest t = cls.newInstance();
             t.init();
-            ComponentContainer c = t.getMainWindow().getContent();
+            Component c = t.getMainWindow().getContent();
             t.getMainWindow().setContent(null);
             return c;
         } catch (InstantiationException e) {
diff --git a/uitest/src/com/vaadin/tests/ScrollbarStressTest.java b/uitest/src/com/vaadin/tests/ScrollbarStressTest.java
index c671c5aa71..c72817ac41 100644
--- a/uitest/src/com/vaadin/tests/ScrollbarStressTest.java
+++ b/uitest/src/com/vaadin/tests/ScrollbarStressTest.java
@@ -126,7 +126,7 @@ public class ScrollbarStressTest extends LegacyApplication {
 
         el.addComponent(ol);
 
-        main.getContent().addComponent(el);
+        main.addComponent(el);
         main.removeWindow(subwindow);
 
     }
diff --git a/uitest/src/com/vaadin/tests/application/DeploymentConfigurationTest.java b/uitest/src/com/vaadin/tests/application/DeploymentConfigurationTest.java
index 9c89254bd7..799622b31d 100644
--- a/uitest/src/com/vaadin/tests/application/DeploymentConfigurationTest.java
+++ b/uitest/src/com/vaadin/tests/application/DeploymentConfigurationTest.java
@@ -5,15 +5,20 @@ import java.util.Properties;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 public class DeploymentConfigurationTest extends UI {
 
     @Override
     protected void init(VaadinRequest request) {
+        VerticalLayout layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
+
         Properties params = getSession().getConfiguration().getInitParameters();
 
         for (Object key : params.keySet()) {
-            addComponent(new Label(key + ": "
+            layout.addComponent(new Label(key + ": "
                     + params.getProperty((String) key)));
         }
     }
diff --git a/uitest/src/com/vaadin/tests/components/AbstractComponentContainerTest.java b/uitest/src/com/vaadin/tests/components/AbstractComponentContainerTest.java
index be3b7760f2..146e996eaf 100644
--- a/uitest/src/com/vaadin/tests/components/AbstractComponentContainerTest.java
+++ b/uitest/src/com/vaadin/tests/components/AbstractComponentContainerTest.java
@@ -7,10 +7,10 @@ import java.util.LinkedHashMap;
 import com.vaadin.ui.AbstractComponentContainer;
 import com.vaadin.ui.Button;
 import com.vaadin.ui.Component;
-import com.vaadin.ui.ComponentContainer.ComponentAttachEvent;
-import com.vaadin.ui.ComponentContainer.ComponentAttachListener;
-import com.vaadin.ui.ComponentContainer.ComponentDetachEvent;
-import com.vaadin.ui.ComponentContainer.ComponentDetachListener;
+import com.vaadin.ui.HasComponents.ComponentAttachEvent;
+import com.vaadin.ui.HasComponents.ComponentAttachListener;
+import com.vaadin.ui.HasComponents.ComponentDetachEvent;
+import com.vaadin.ui.HasComponents.ComponentDetachListener;
 import com.vaadin.ui.HorizontalSplitPanel;
 import com.vaadin.ui.InlineDateField;
 import com.vaadin.ui.NativeButton;
diff --git a/uitest/src/com/vaadin/tests/components/AbstractTestUI.java b/uitest/src/com/vaadin/tests/components/AbstractTestUI.java
index 480fd2df57..a044b52f18 100644
--- a/uitest/src/com/vaadin/tests/components/AbstractTestUI.java
+++ b/uitest/src/com/vaadin/tests/components/AbstractTestUI.java
@@ -17,10 +17,14 @@ public abstract class AbstractTestUI extends UI {
         Label label = new Label(getTestDescription(), ContentMode.HTML);
         label.setWidth("100%");
 
+        VerticalLayout rootLayout = new VerticalLayout();
+        rootLayout.setMargin(true);
+        setContent(rootLayout);
+
         layout = new VerticalLayout();
 
-        getContent().addComponent(label);
-        getContent().addComponent(layout);
+        rootLayout.addComponent(label);
+        rootLayout.addComponent(layout);
         ((VerticalLayout) getContent()).setExpandRatio(layout, 1);
 
         setup(request);
@@ -34,17 +38,14 @@ public abstract class AbstractTestUI extends UI {
 
     protected abstract void setup(VaadinRequest request);
 
-    @Override
     public void addComponent(Component c) {
         getLayout().addComponent(c);
     }
 
-    @Override
     public void removeComponent(Component c) {
         getLayout().removeComponent(c);
     }
 
-    @Override
     public void replaceComponent(Component oldComponent, Component newComponent) {
         getLayout().replaceComponent(oldComponent, newComponent);
     }
diff --git a/uitest/src/com/vaadin/tests/components/LayoutAttachListenerInfo.java b/uitest/src/com/vaadin/tests/components/LayoutAttachListenerInfo.java
index 6e54c0d9f4..b815705883 100644
--- a/uitest/src/com/vaadin/tests/components/LayoutAttachListenerInfo.java
+++ b/uitest/src/com/vaadin/tests/components/LayoutAttachListenerInfo.java
@@ -7,9 +7,9 @@ import com.vaadin.data.Property.ValueChangeListener;
 import com.vaadin.ui.AbsoluteLayout;
 import com.vaadin.ui.Button;
 import com.vaadin.ui.Button.ClickEvent;
-import com.vaadin.ui.ComponentContainer;
-import com.vaadin.ui.ComponentContainer.ComponentAttachEvent;
 import com.vaadin.ui.GridLayout;
+import com.vaadin.ui.HasComponents.ComponentAttachEvent;
+import com.vaadin.ui.HasComponents.ComponentAttachListener;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.Notification;
 import com.vaadin.ui.OptionGroup;
@@ -26,7 +26,7 @@ public class LayoutAttachListenerInfo extends TestBase {
                 "AbsoluteLayout", "OrderedLayout", "GridLayout"));
         layouts.select("AbsoluteLayout");
         layouts.setImmediate(true);
-        layouts.addListener(new ValueChangeListener() {
+        layouts.addValueChangeListener(new ValueChangeListener() {
             @Override
             public void valueChange(ValueChangeEvent event) {
                 if (event.getProperty().getValue().equals("AbsoluteLayout")) {
@@ -64,7 +64,7 @@ public class LayoutAttachListenerInfo extends TestBase {
         final AbsoluteLayout a = new AbsoluteLayout();
         a.setWidth("300px");
         a.setHeight("300px");
-        a.addListener(new ComponentContainer.ComponentAttachListener() {
+        a.addComponentAttachListener(new ComponentAttachListener() {
             @Override
             public void componentAttachedToContainer(ComponentAttachEvent event) {
                 AbsoluteLayout layout = (AbsoluteLayout) event.getContainer();
@@ -93,7 +93,7 @@ public class LayoutAttachListenerInfo extends TestBase {
         final VerticalLayout v = new VerticalLayout();
         v.setWidth("300px");
         v.setHeight("300px");
-        v.addListener(new ComponentContainer.ComponentAttachListener() {
+        v.addComponentAttachListener(new ComponentAttachListener() {
             @Override
             public void componentAttachedToContainer(ComponentAttachEvent event) {
                 VerticalLayout layout = (VerticalLayout) event.getContainer();
@@ -122,7 +122,7 @@ public class LayoutAttachListenerInfo extends TestBase {
         final GridLayout g = new GridLayout(4, 4);
         g.setWidth("300px");
         g.setHeight("300px");
-        g.addListener(new ComponentContainer.ComponentAttachListener() {
+        g.addComponentAttachListener(new ComponentAttachListener() {
             @Override
             public void componentAttachedToContainer(ComponentAttachEvent event) {
                 GridLayout layout = (GridLayout) event.getContainer();
diff --git a/uitest/src/com/vaadin/tests/components/TestBase.java b/uitest/src/com/vaadin/tests/components/TestBase.java
index 08e39f7e6f..b500a1144b 100644
--- a/uitest/src/com/vaadin/tests/components/TestBase.java
+++ b/uitest/src/com/vaadin/tests/components/TestBase.java
@@ -16,10 +16,10 @@ public abstract class TestBase extends AbstractTestCase {
 
         Label label = new Label(getDescription(), ContentMode.HTML);
         label.setWidth("100%");
-        window.getContent().addComponent(label);
+        window.addComponent(label);
 
         layout = new VerticalLayout();
-        window.getContent().addComponent(layout);
+        window.addComponent(layout);
         ((VerticalLayout) window.getContent()).setExpandRatio(layout, 1);
 
         setup();
diff --git a/uitest/src/com/vaadin/tests/components/abstractcomponent/AllComponentTooltipTest.java b/uitest/src/com/vaadin/tests/components/abstractcomponent/AllComponentTooltipTest.java
index 3473f50ee5..4b2b1f81ce 100644
--- a/uitest/src/com/vaadin/tests/components/abstractcomponent/AllComponentTooltipTest.java
+++ b/uitest/src/com/vaadin/tests/components/abstractcomponent/AllComponentTooltipTest.java
@@ -27,7 +27,8 @@ public class AllComponentTooltipTest extends AbstractTestUI {
 
     @Override
     protected void setup(VaadinRequest request) {
-        setContent(new GridLayout(5, 5));
+        GridLayout layout = new GridLayout(5, 5);
+        setContent(layout);
         for (Class<? extends Component> cls : VaadinClasses.getComponents()) {
             try {
                 AbstractComponent c = (AbstractComponent) cls.newInstance();
@@ -40,7 +41,7 @@ public class AllComponentTooltipTest extends AbstractTestUI {
                 c.setDescription(cls.getName());
                 c.setWidth("100px");
                 c.setHeight("100px");
-                getContent().addComponent(c);
+                layout.addComponent(c);
                 System.out.println("Added " + cls.getName());
             } catch (Exception e) {
                 System.err.println("Could not instatiate " + cls.getName());
diff --git a/uitest/src/com/vaadin/tests/components/menubar/MenuBarRunsOutOfBrowser.java b/uitest/src/com/vaadin/tests/components/menubar/MenuBarRunsOutOfBrowser.java
index 78c6d92ee2..0d9c3d8bba 100644
--- a/uitest/src/com/vaadin/tests/components/menubar/MenuBarRunsOutOfBrowser.java
+++ b/uitest/src/com/vaadin/tests/components/menubar/MenuBarRunsOutOfBrowser.java
@@ -23,7 +23,7 @@ public class MenuBarRunsOutOfBrowser extends AbstractTestCase {
         menuBar.addItem("ABC", new ThemeResource("icons/16/document.png"), null);
         menuBar.addItem("123", new ThemeResource("icons/16/help.png"), null);
 
-        main.getContent().addComponent(menuBar);
+        main.addComponent(menuBar);
         ((VerticalLayout) main.getContent()).setComponentAlignment(menuBar,
                 Alignment.TOP_RIGHT);
 
diff --git a/uitest/src/com/vaadin/tests/components/table/TableInTabsheet.java b/uitest/src/com/vaadin/tests/components/table/TableInTabsheet.java
index a9cecfd6b5..ee9609bb96 100644
--- a/uitest/src/com/vaadin/tests/components/table/TableInTabsheet.java
+++ b/uitest/src/com/vaadin/tests/components/table/TableInTabsheet.java
@@ -18,7 +18,6 @@ public class TableInTabsheet extends AbstractTestUI {
 
     @Override
     protected void setup(VaadinRequest request) {
-        getUI().setCaption("test");
         VerticalLayout vPrinc = new VerticalLayout();
         vPrinc.setStyleName(Reindeer.LAYOUT_BLUE);
 
diff --git a/uitest/src/com/vaadin/tests/components/ui/LazyInitUIs.java b/uitest/src/com/vaadin/tests/components/ui/LazyInitUIs.java
index 1064f2e766..57fc9f3e62 100644
--- a/uitest/src/com/vaadin/tests/components/ui/LazyInitUIs.java
+++ b/uitest/src/com/vaadin/tests/components/ui/LazyInitUIs.java
@@ -11,6 +11,7 @@ import com.vaadin.tests.components.AbstractTestUIProvider;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.Link;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 public class LazyInitUIs extends AbstractTestUIProvider {
 
@@ -18,7 +19,11 @@ public class LazyInitUIs extends AbstractTestUIProvider {
     private static class EagerInitUI extends UI {
         @Override
         public void init(VaadinRequest request) {
-            addComponent(getRequestInfo("EagerInitUI", request));
+            VerticalLayout layout = new VerticalLayout();
+            layout.setMargin(true);
+            setContent(layout);
+
+            layout.addComponent(getRequestInfo("EagerInitUI", request));
         }
     }
 
@@ -39,7 +44,11 @@ public class LazyInitUIs extends AbstractTestUIProvider {
             UI uI = new UI() {
                 @Override
                 protected void init(VaadinRequest request) {
-                    addComponent(getRequestInfo("LazyCreateUI", request));
+                    VerticalLayout layout = new VerticalLayout();
+                    layout.setMargin(true);
+                    setContent(layout);
+
+                    layout.addComponent(getRequestInfo("LazyCreateUI", request));
                 }
             };
             return uI;
@@ -51,20 +60,24 @@ public class LazyInitUIs extends AbstractTestUIProvider {
             UI uI = new UI() {
                 @Override
                 protected void init(VaadinRequest request) {
-                    addComponent(getRequestInfo("NormalUI", request));
+                    VerticalLayout layout = new VerticalLayout();
+                    layout.setMargin(true);
+                    setContent(layout);
+
+                    layout.addComponent(getRequestInfo("NormalUI", request));
 
                     String location = getPage().getLocation().toString();
                     Link lazyCreateLink = new Link("Open lazyCreate UI",
                             new ExternalResource(location.replaceFirst(
                                     "(\\?|#|$).*", "?lazyCreate#lazyCreate")));
                     lazyCreateLink.setTargetName("_blank");
-                    addComponent(lazyCreateLink);
+                    layout.addComponent(lazyCreateLink);
 
                     Link lazyInitLink = new Link("Open eagerInit UI",
                             new ExternalResource(location.replaceFirst(
                                     "(\\?|#|$).*", "?eagerInit#eagerInit")));
                     lazyInitLink.setTargetName("_blank");
-                    addComponent(lazyInitLink);
+                    layout.addComponent(lazyInitLink);
                 }
             };
 
diff --git a/uitest/src/com/vaadin/tests/components/ui/UIsInMultipleTabs.java b/uitest/src/com/vaadin/tests/components/ui/UIsInMultipleTabs.java
index 8c4ba3980d..53df69f028 100644
--- a/uitest/src/com/vaadin/tests/components/ui/UIsInMultipleTabs.java
+++ b/uitest/src/com/vaadin/tests/components/ui/UIsInMultipleTabs.java
@@ -9,6 +9,7 @@ import com.vaadin.server.VaadinServiceSession;
 import com.vaadin.tests.components.AbstractTestUIProvider;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 public class UIsInMultipleTabs extends AbstractTestUIProvider {
     // No cleanup -> will leak, but shouldn't matter for tests
@@ -29,7 +30,11 @@ public class UIsInMultipleTabs extends AbstractTestUIProvider {
             int currentCount = count.incrementAndGet();
             String message = "This is UI number " + currentCount;
 
-            addComponent(new Label(message));
+            VerticalLayout layout = new VerticalLayout();
+            layout.setMargin(true);
+            setContent(layout);
+
+            layout.addComponent(new Label(message));
         }
     }
 
diff --git a/uitest/src/com/vaadin/tests/components/window/SubWindowFocusAndBlurListeners.java b/uitest/src/com/vaadin/tests/components/window/SubWindowFocusAndBlurListeners.java
index bb247ee065..bb5a817362 100644
--- a/uitest/src/com/vaadin/tests/components/window/SubWindowFocusAndBlurListeners.java
+++ b/uitest/src/com/vaadin/tests/components/window/SubWindowFocusAndBlurListeners.java
@@ -10,6 +10,7 @@ import com.vaadin.event.ShortcutAction;
 import com.vaadin.tests.components.TestBase;
 import com.vaadin.ui.Button;
 import com.vaadin.ui.Button.ClickEvent;
+import com.vaadin.ui.ComponentContainer;
 import com.vaadin.ui.Notification;
 import com.vaadin.ui.TextField;
 import com.vaadin.ui.UI;
@@ -68,7 +69,7 @@ public class SubWindowFocusAndBlurListeners extends TestBase {
 
         main.addWindow(window);
 
-        main.addComponent(new TextField());
+        ((ComponentContainer) main.getContent()).addComponent(new TextField());
 
         Button button = new Button("Bring to front (should focus too)",
                 new Button.ClickListener() {
@@ -77,7 +78,7 @@ public class SubWindowFocusAndBlurListeners extends TestBase {
                         window.bringToFront();
                     }
                 });
-        main.addComponent(button);
+        ((ComponentContainer) main.getContent()).addComponent(button);
 
         Window window2 = new Window("Another window for testing");
         main.addWindow(window2);
diff --git a/uitest/src/com/vaadin/tests/integration/IntegrationTestUI.java b/uitest/src/com/vaadin/tests/integration/IntegrationTestUI.java
index 61214ede8c..0e6cb19b30 100755
--- a/uitest/src/com/vaadin/tests/integration/IntegrationTestUI.java
+++ b/uitest/src/com/vaadin/tests/integration/IntegrationTestUI.java
@@ -9,10 +9,15 @@ import com.vaadin.server.VaadinRequest;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.Table;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 public class IntegrationTestUI extends UI {
     @Override
     protected void init(VaadinRequest request) {
+        VerticalLayout layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
+
         final Table table = new Table();
         table.addContainerProperty("icon", Resource.class, null);
         table.setItemIconPropertyId("icon");
@@ -21,7 +26,7 @@ public class IntegrationTestUI extends UI {
         table.setImmediate(true);
         table.setSelectable(true);
         table.setVisibleColumns(new Object[] { "country" });
-        addComponent(table);
+        layout.addComponent(table);
 
         Item item = table.addItem("FI");
         item.getItemProperty("icon").setValue(new ClassResource("fi.gif"));
@@ -37,6 +42,6 @@ public class IntegrationTestUI extends UI {
                 selectedLabel.setValue(String.valueOf(table.getValue()));
             }
         });
-        addComponent(selectedLabel);
+        layout.addComponent(selectedLabel);
     }
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a1/AutoGeneratingForm.java b/uitest/src/com/vaadin/tests/minitutorials/v7a1/AutoGeneratingForm.java
index 4111f6c07a..53d76a251f 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a1/AutoGeneratingForm.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a1/AutoGeneratingForm.java
@@ -21,6 +21,7 @@ import com.vaadin.data.fieldgroup.FieldGroup;
 import com.vaadin.data.util.BeanItem;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 /**
  * Mini tutorial code for
@@ -34,6 +35,10 @@ public class AutoGeneratingForm extends UI {
 
     @Override
     protected void init(VaadinRequest request) {
+        VerticalLayout layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
+
         FieldGroup fieldGroup = new BeanFieldGroup<Person>(Person.class);
 
         // We need an item data source before we create the fields to be able to
@@ -44,7 +49,7 @@ public class AutoGeneratingForm extends UI {
         // Loop through the properties, build fields for them and add the fields
         // to this root
         for (Object propertyId : fieldGroup.getUnboundPropertyIds()) {
-            addComponent(fieldGroup.buildAndBind(propertyId));
+            layout.addComponent(fieldGroup.buildAndBind(propertyId));
         }
     }
 
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a1/CreatingPreserveState.java b/uitest/src/com/vaadin/tests/minitutorials/v7a1/CreatingPreserveState.java
index ffe1f09216..66de5af27e 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a1/CreatingPreserveState.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a1/CreatingPreserveState.java
@@ -37,7 +37,7 @@ public class CreatingPreserveState extends UI {
     public void init(VaadinRequest request) {
         TextField tf = new TextField("Window #" + (++windowCounter));
         tf.setImmediate(true);
-        getContent().addComponent(tf);
+        setContent(tf);
     }
 
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a1/DifferentFeaturesForDifferentClients.java b/uitest/src/com/vaadin/tests/minitutorials/v7a1/DifferentFeaturesForDifferentClients.java
index 737de10894..6a713c4f64 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a1/DifferentFeaturesForDifferentClients.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a1/DifferentFeaturesForDifferentClients.java
@@ -59,8 +59,7 @@ public class DifferentFeaturesForDifferentClients extends UIProvider {
 class DefaultRoot extends UI {
     @Override
     protected void init(VaadinRequest request) {
-        getContent().addComponent(
-                new Label("This browser does not support touch events"));
+        setContent(new Label("This browser does not support touch events"));
     }
 }
 
@@ -70,8 +69,7 @@ class TouchRoot extends UI {
         WebBrowser webBrowser = getSession().getBrowser();
         String screenSize = "" + webBrowser.getScreenWidth() + "x"
                 + webBrowser.getScreenHeight();
-        getContent().addComponent(
-                new Label("Using a touch enabled device with screen size"
-                        + screenSize));
+        setContent(new Label("Using a touch enabled device with screen size"
+                + screenSize));
     }
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a1/DynamicImageUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a1/DynamicImageUI.java
index 61cbd94f3a..a84a2206ef 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a1/DynamicImageUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a1/DynamicImageUI.java
@@ -25,7 +25,7 @@ public class DynamicImageUI extends AbstractTestUI {
         // Add an image using the resource
         Image image = new Image("A dynamically generated image", resource);
 
-        getContent().addComponent(image);
+        addComponent(image);
     }
 
     @Override
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a1/FindCurrentUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a1/FindCurrentUI.java
index ebacb2f672..ba7ef78ec1 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a1/FindCurrentUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a1/FindCurrentUI.java
@@ -55,7 +55,7 @@ public class FindCurrentUI extends UI {
             }
         });
 
-        addComponent(helloButton);
+        setContent(helloButton);
     }
 
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingBeanValidation.java b/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingBeanValidation.java
index 51c7cbbe60..fa0a8e8c31 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingBeanValidation.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingBeanValidation.java
@@ -77,7 +77,7 @@ public class UsingBeanValidation extends UI {
         TextField firstName = new TextField("First name",
                 item.getItemProperty("name"));
         firstName.setImmediate(true);
-        addComponent(firstName);
+        setContent(firstName);
 
         firstName.addValidator(new BeanValidator(Person.class, "name"));
     }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingUriFragments.java b/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingUriFragments.java
index 15c4fa838e..f3bef99e65 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingUriFragments.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingUriFragments.java
@@ -23,6 +23,7 @@ import com.vaadin.ui.Button;
 import com.vaadin.ui.Button.ClickEvent;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 /**
  * Mini tutorial code for
@@ -33,11 +34,17 @@ import com.vaadin.ui.UI;
  */
 public class UsingUriFragments extends UI {
 
+    private VerticalLayout layout;
+
     @Override
     protected void init(VaadinRequest request) {
+        layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
+
         Label label = new Label("Hello, your fragment is "
                 + getPage().getUriFragment());
-        getContent().addComponent(label);
+        layout.addComponent(label);
 
         // React to fragment changes
         getPage().addListener(new UriFragmentChangedListener() {
@@ -50,7 +57,7 @@ public class UsingUriFragments extends UI {
         // Handle the fragment received in the initial request
         handleFragment(getPage().getUriFragment());
 
-        addComponent(new Button("Show and set fragment",
+        layout.addComponent(new Button("Show and set fragment",
                 new Button.ClickListener() {
                     @Override
                     public void buttonClick(ClickEvent event) {
@@ -61,7 +68,7 @@ public class UsingUriFragments extends UI {
     }
 
     private void handleFragment(String uriFragment) {
-        addComponent(new Label("Got new fragment: " + uriFragment));
+        layout.addComponent(new Label("Got new fragment: " + uriFragment));
     }
 
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingXyzWhenInitializing.java b/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingXyzWhenInitializing.java
index 52499ffbe5..c4d496641d 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingXyzWhenInitializing.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a1/UsingXyzWhenInitializing.java
@@ -19,6 +19,7 @@ package com.vaadin.tests.minitutorials.v7a1;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 /**
  * Mini tutorial code for
@@ -32,18 +33,22 @@ public class UsingXyzWhenInitializing extends UI {
 
     @Override
     protected void init(VaadinRequest request) {
+        VerticalLayout layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
+
         String name = request.getParameter("name");
         if (name == null) {
             name = "Unknown";
         }
 
-        getContent().addComponent(new Label("Hello " + name));
+        layout.addComponent(new Label("Hello " + name));
 
         String pathInfo = request.getRequestPathInfo();
         if ("/viewSource".equals(pathInfo)) {
-            getContent().addComponent(new Label("This is the source"));
+            layout.addComponent(new Label("This is the source"));
         } else {
-            getContent().addComponent(new Label("Welcome to my application"));
+            layout.addComponent(new Label("Welcome to my application"));
         }
 
         // WebBrowser browser = request.getBrowserDetails().getWebBrowser();
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a2/ComponentInStateUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a2/ComponentInStateUI.java
index da178167ed..986811e0f4 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a2/ComponentInStateUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a2/ComponentInStateUI.java
@@ -4,6 +4,7 @@ import com.vaadin.annotations.Widgetset;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 /**
  * Mini tutorial code for
@@ -17,10 +18,14 @@ import com.vaadin.ui.UI;
 public class ComponentInStateUI extends UI {
     @Override
     protected void init(VaadinRequest request) {
+        VerticalLayout layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
+
         ComponentInStateComponent component = new ComponentInStateComponent();
         component.setOtherComponent(this);
-        addComponent(component);
-        addComponent(new Label("Server-side type of other component: "
+        layout.addComponent(component);
+        layout.addComponent(new Label("Server-side type of other component: "
                 + component.getOtherComponent().getClass().getName()));
     }
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a2/MyComponentUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a2/MyComponentUI.java
index caf38077bf..80aeecfa79 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a2/MyComponentUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a2/MyComponentUI.java
@@ -41,7 +41,7 @@ public class MyComponentUI extends UI {
 
         component.setText("My component text");
 
-        addComponent(component);
+        setContent(component);
     }
 
 }
\ No newline at end of file
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a2/ResourceInStateUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a2/ResourceInStateUI.java
index 155c1d9ded..4ddf86c345 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a2/ResourceInStateUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a2/ResourceInStateUI.java
@@ -37,7 +37,7 @@ public class ResourceInStateUI extends UI {
         ResourceInStateComponent component = new ResourceInStateComponent();
         component.setMyIcon(new ThemeResource("../runo/icons/32/calendar.png"));
 
-        addComponent(component);
+        setContent(component);
     }
 
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a2/WidgetcontainerUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a2/WidgetcontainerUI.java
index f7cf6b4270..d81e6b4c59 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a2/WidgetcontainerUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a2/WidgetcontainerUI.java
@@ -11,15 +11,20 @@ import com.vaadin.ui.CheckBox;
 import com.vaadin.ui.Component;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 @Widgetset("com.vaadin.tests.widgetset.TestingWidgetSet")
 public class WidgetcontainerUI extends UI {
     @Override
     public void init(VaadinRequest request) {
+        VerticalLayout layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
+
         Label label = new Label("Hello Vaadin user");
-        addComponent(label);
+        layout.addComponent(label);
         final WidgetContainer widgetContainer = new WidgetContainer();
-        addComponent(widgetContainer);
+        layout.addComponent(widgetContainer);
         widgetContainer.addComponent(new Label(
                 "Click the button to add components to the WidgetContainer."));
         Button button = new Button("Add more components", new ClickListener() {
@@ -39,7 +44,7 @@ public class WidgetcontainerUI extends UI {
                 widgetContainer.addComponent(component);
             }
         });
-        addComponent(button);
+        layout.addComponent(button);
     }
 
 }
\ No newline at end of file
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a3/AnalyticsUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a3/AnalyticsUI.java
index 980d0b90b2..8bc9619902 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a3/AnalyticsUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a3/AnalyticsUI.java
@@ -28,7 +28,7 @@ public class AnalyticsUI extends UI {
         final Analytics analytics = new Analytics("UA-33036133-12");
         analytics.extend(this);
 
-        addComponent(new Button("Track pageview", new Button.ClickListener() {
+        setContent(new Button("Track pageview", new Button.ClickListener() {
             @Override
             public void buttonClick(ClickEvent event) {
                 analytics.trackPageview("/fake/url");
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a3/ComplexTypesUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a3/ComplexTypesUI.java
index 792be69410..fd271db7e6 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a3/ComplexTypesUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a3/ComplexTypesUI.java
@@ -25,7 +25,7 @@ public class ComplexTypesUI extends UI {
     protected void init(VaadinRequest request) {
         ComplexTypesComponent complexTypesComponent = new ComplexTypesComponent();
         complexTypesComponent.sendComplexTypes();
-        addComponent(complexTypesComponent);
+        setContent(complexTypesComponent);
     }
 
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a3/FlotJavaScriptUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a3/FlotJavaScriptUI.java
index a3ed5fe11e..d1d9879a31 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a3/FlotJavaScriptUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a3/FlotJavaScriptUI.java
@@ -20,24 +20,30 @@ import com.vaadin.server.VaadinRequest;
 import com.vaadin.ui.Button;
 import com.vaadin.ui.Button.ClickEvent;
 import com.vaadin.ui.UI;
+import com.vaadin.ui.VerticalLayout;
 
 public class FlotJavaScriptUI extends UI {
 
     @Override
     protected void init(VaadinRequest request) {
+        VerticalLayout layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
+
         final Flot flot = new Flot();
         flot.setHeight("300px");
         flot.setWidth("400px");
 
         flot.addSeries(1, 2, 4, 8, 16);
-        addComponent(flot);
-
-        addComponent(new Button("Highlight point", new Button.ClickListener() {
-            @Override
-            public void buttonClick(ClickEvent event) {
-                flot.highlight(0, 3);
-            }
-        }));
+        layout.addComponent(flot);
+
+        layout.addComponent(new Button("Highlight point",
+                new Button.ClickListener() {
+                    @Override
+                    public void buttonClick(ClickEvent event) {
+                        flot.highlight(0, 3);
+                    }
+                }));
     }
 
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a3/JSAPIUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a3/JSAPIUI.java
index ad4139d883..f9d79a518e 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a3/JSAPIUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a3/JSAPIUI.java
@@ -39,7 +39,7 @@ public class JSAPIUI extends UI {
                     }
                 });
 
-        addComponent(new Link(
+        setContent(new Link(
                 "Send message",
                 new ExternalResource(
                         "javascript:(function(){com.example.api.notify(prompt('Message'),2);})();")));
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7a3/RedButtonUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7a3/RedButtonUI.java
index 18b4b1430e..a4d4031d5f 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7a3/RedButtonUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7a3/RedButtonUI.java
@@ -22,6 +22,6 @@ import com.vaadin.ui.UI;
 public class RedButtonUI extends UI {
     @Override
     protected void init(VaadinRequest request) {
-        addComponent(new RedButton("My red button"));
+        setContent(new RedButton("My red button"));
     }
 }
\ No newline at end of file
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7b5/SettingReadingSessionAttributesUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7b5/SettingReadingSessionAttributesUI.java
index bc96152880..99b5973661 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7b5/SettingReadingSessionAttributesUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7b5/SettingReadingSessionAttributesUI.java
@@ -36,22 +36,28 @@ public class SettingReadingSessionAttributesUI extends UI {
 
     @Override
     protected void init(VaadinRequest request) {
-        addComponent(statusHolder);
-        addComponent(textField);
-        addComponent(new Button("Set new values", new Button.ClickListener() {
-            @Override
-            public void buttonClick(ClickEvent event) {
-                String value = textField.getValue();
+        VerticalLayout layout = new VerticalLayout();
+        layout.setMargin(true);
+        setContent(layout);
 
-                saveValue(SettingReadingSessionAttributesUI.this, value);
-            }
-        }));
-        addComponent(new Button("Reload page", new Button.ClickListener() {
-            @Override
-            public void buttonClick(ClickEvent event) {
-                getPage().setLocation(getPage().getLocation());
-            }
-        }));
+        layout.addComponent(statusHolder);
+        layout.addComponent(textField);
+        layout.addComponent(new Button("Set new values",
+                new Button.ClickListener() {
+                    @Override
+                    public void buttonClick(ClickEvent event) {
+                        String value = textField.getValue();
+
+                        saveValue(SettingReadingSessionAttributesUI.this, value);
+                    }
+                }));
+        layout.addComponent(new Button("Reload page",
+                new Button.ClickListener() {
+                    @Override
+                    public void buttonClick(ClickEvent event) {
+                        getPage().setLocation(getPage().getLocation());
+                    }
+                }));
 
         showValue(this);
     }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7b6/LettingUserDownladFile.java b/uitest/src/com/vaadin/tests/minitutorials/v7b6/LettingUserDownloadFile.java
index e6a6e267a9..d5c99c931b 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7b6/LettingUserDownladFile.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7b6/LettingUserDownloadFile.java
@@ -31,7 +31,7 @@ import com.vaadin.server.VaadinRequest;
 import com.vaadin.ui.Button;
 import com.vaadin.ui.UI;
 
-public class LettingUserDownladFile extends UI {
+public class LettingUserDownloadFile extends UI {
 
     @Override
     protected void init(VaadinRequest request) {
@@ -41,7 +41,7 @@ public class LettingUserDownladFile extends UI {
         FileDownloader fileDownloader = new FileDownloader(myResource);
         fileDownloader.extend(downloadButton);
 
-        addComponent(downloadButton);
+        setContent(downloadButton);
     }
 
     private StreamResource createResource() {
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7b6/MyPopupUI.java b/uitest/src/com/vaadin/tests/minitutorials/v7b6/MyPopupUI.java
index 2c50b62d0d..59f5831468 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7b6/MyPopupUI.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7b6/MyPopupUI.java
@@ -24,7 +24,7 @@ public class MyPopupUI extends UI {
 
     @Override
     protected void init(VaadinRequest request) {
-        addComponent(new Label("This is MyPopupUI"));
+        setContent(new Label("This is MyPopupUI"));
     }
 
 }
diff --git a/uitest/src/com/vaadin/tests/minitutorials/v7b6/OpeningUIInPopup.java b/uitest/src/com/vaadin/tests/minitutorials/v7b6/OpeningUIInPopup.java
index f1db0fc478..7fd8373bbd 100644
--- a/uitest/src/com/vaadin/tests/minitutorials/v7b6/OpeningUIInPopup.java
+++ b/uitest/src/com/vaadin/tests/minitutorials/v7b6/OpeningUIInPopup.java
@@ -31,7 +31,7 @@ public class OpeningUIInPopup extends UI {
         popupOpener.setFeatures("height=300,width=300");
         popupOpener.extend(popupButton);
 
-        addComponent(popupButton);
+        setContent(popupButton);
     }
 
 }
diff --git a/uitest/src/com/vaadin/tests/navigator/NavigatorTest.java b/uitest/src/com/vaadin/tests/navigator/NavigatorTest.java
index 97c4e9fd4f..08832e5e82 100644
--- a/uitest/src/com/vaadin/tests/navigator/NavigatorTest.java
+++ b/uitest/src/com/vaadin/tests/navigator/NavigatorTest.java
@@ -113,6 +113,10 @@ public class NavigatorTest extends UI {
     @Override
     protected void init(VaadinRequest req) {
         try {
+            VerticalLayout layout = new VerticalLayout();
+            layout.setMargin(true);
+            setContent(layout);
+
             navi = new Navigator(this, naviLayout);
 
             navi.addView("", new DefaultView());
@@ -127,13 +131,13 @@ public class NavigatorTest extends UI {
 
             navi.navigate();
 
-            addComponent(new NaviButton("list"));
-            addComponent(new NaviButton("edit"));
-            addComponent(new NaviButton("forbidden"));
+            layout.addComponent(new NaviButton("list"));
+            layout.addComponent(new NaviButton("edit"));
+            layout.addComponent(new NaviButton("forbidden"));
 
-            addComponent(params);
-            addComponent(log);
-            addComponent(naviLayout);
+            layout.addComponent(params);
+            layout.addComponent(log);
+            layout.addComponent(naviLayout);
         } catch (Exception e) {
             e.printStackTrace();
             log.log("Exception: " + e);
diff --git a/uitest/src/com/vaadin/tests/tickets/Ticket2021.java b/uitest/src/com/vaadin/tests/tickets/Ticket2021.java
index 3f798a3e19..938df7befc 100644
--- a/uitest/src/com/vaadin/tests/tickets/Ticket2021.java
+++ b/uitest/src/com/vaadin/tests/tickets/Ticket2021.java
@@ -38,7 +38,7 @@ public class Ticket2021 extends LegacyApplication {
         p.setContent(new VerticalLayout());
         p.getContent().setSizeFull();
 
-        w.getContent().addComponent(p);
+        w.addComponent(p);
 
         tf1 = new TextArea();
         tf1.setRows(5);
@@ -59,7 +59,7 @@ public class Ticket2021 extends LegacyApplication {
         p2.setContent(new VerticalLayout());
         p2.getContent().setSizeFull();
 
-        w.getContent().addComponent(p2);
+        w.addComponent(p2);
 
         tf2 = new TextArea();
         tf2.setRows(5);
@@ -85,7 +85,7 @@ public class Ticket2021 extends LegacyApplication {
         gl.setSizeFull();
         gl.setMargin(false);
         p3.getContent().addComponent(gl);
-        w.getContent().addComponent(p3);
+        w.addComponent(p3);
 
         tf3 = new TextArea();
         tf3.setRows(5);
diff --git a/uitest/src/com/vaadin/tests/tickets/Ticket2024.java b/uitest/src/com/vaadin/tests/tickets/Ticket2024.java
index c38ba7822a..2861c9beca 100644
--- a/uitest/src/com/vaadin/tests/tickets/Ticket2024.java
+++ b/uitest/src/com/vaadin/tests/tickets/Ticket2024.java
@@ -19,7 +19,7 @@ public class Ticket2024 extends LegacyApplication {
         layout.setWidth("700");
         w.getContent().setSizeFull();
         w.getContent().setHeight("2000");
-        w.getContent().addComponent(layout);
+        w.addComponent(layout);
 
         layout.addComponent(new Label(
                 "This should NOT get stuck when scrolling down"));
@@ -28,7 +28,7 @@ public class Ticket2024 extends LegacyApplication {
         VerticalLayout ol = new VerticalLayout();
         ol.setHeight("1000");
         ol.setWidth("200");
-        w.getContent().addComponent(ol);
+        w.addComponent(ol);
         ol.addComponent(new Label("Just a label to enable the scrollbar"));
 
     }
diff --git a/uitest/src/com/vaadin/tests/tickets/Ticket2029.java b/uitest/src/com/vaadin/tests/tickets/Ticket2029.java
index 8031041e5b..db3334d570 100644
--- a/uitest/src/com/vaadin/tests/tickets/Ticket2029.java
+++ b/uitest/src/com/vaadin/tests/tickets/Ticket2029.java
@@ -32,9 +32,9 @@ public class Ticket2029 extends LegacyApplication {
         setMainWindow(w);
         // setTheme("tests-tickets");
         Panel p = createPanel();
-        w.getContent().addComponent(p);
+        w.addComponent(p);
         // w.getLayout().addComponent(createGLPanel());
-        w.getContent().addComponent(createPanelV());
+        w.addComponent(createPanelV());
     }
 
     private Panel createPanel() {
diff --git a/uitest/src/com/vaadin/tests/tickets/Ticket2048.java b/uitest/src/com/vaadin/tests/tickets/Ticket2048.java
index cb6fba3ab8..b2a6e64cd2 100644
--- a/uitest/src/com/vaadin/tests/tickets/Ticket2048.java
+++ b/uitest/src/com/vaadin/tests/tickets/Ticket2048.java
@@ -75,8 +75,7 @@ public class Ticket2048 extends LegacyApplication {
                     public void buttonClick(ClickEvent event) {
                         Embedded newEmbedded = new Embedded(null,
                                 new ThemeResource("icons/64/folder-add.png"));
-                        getMainWindow().getContent().replaceComponent(embedded,
-                                newEmbedded);
+                        getMainWindow().replaceComponent(embedded, newEmbedded);
                         embedded = newEmbedded;
 
                     }
diff --git a/uitest/src/com/vaadin/tests/tickets/Ticket2101.java b/uitest/src/com/vaadin/tests/tickets/Ticket2101.java
index d3e6202542..dd10943108 100644
--- a/uitest/src/com/vaadin/tests/tickets/Ticket2101.java
+++ b/uitest/src/com/vaadin/tests/tickets/Ticket2101.java
@@ -15,7 +15,7 @@ public class Ticket2101 extends LegacyApplication {
                 "Button with a long text which will not fit on 50 pixels");
         b.setWidth("50px");
 
-        w.getContent().addComponent(b);
+        w.addComponent(b);
     }
 
 }
diff --git a/uitest/src/com/vaadin/tests/util/SampleDirectory.java b/uitest/src/com/vaadin/tests/util/SampleDirectory.java
index 504a4e5dfd..2f21026118 100644
--- a/uitest/src/com/vaadin/tests/util/SampleDirectory.java
+++ b/uitest/src/com/vaadin/tests/util/SampleDirectory.java
@@ -23,8 +23,8 @@ import com.vaadin.server.VaadinService;
 import com.vaadin.server.VaadinServiceSession;
 import com.vaadin.shared.ui.label.ContentMode;
 import com.vaadin.ui.Label;
+import com.vaadin.ui.LegacyWindow;
 import com.vaadin.ui.Panel;
-import com.vaadin.ui.UI;
 
 /**
  * Provides sample directory based on application directory. If this fails then
@@ -42,7 +42,8 @@ public class SampleDirectory {
      * @param application
      * @return file pointing to sample directory
      */
-    public static File getDirectory(VaadinServiceSession application, UI uI) {
+    public static File getDirectory(VaadinServiceSession application,
+            LegacyWindow uI) {
         String errorMessage = "Access to application "
                 + "context base directory failed, "
                 + "possible security constraint with Application "
@@ -82,9 +83,9 @@ public class SampleDirectory {
                 "Cannot provide sample directory"));
         errorPanel.addComponent(new Label(errorMessage, ContentMode.HTML));
         // Remove all components from applications main window
-        uI.getContent().removeAllComponents();
+        uI.removeAllComponents();
         // Add error panel
-        uI.getContent().addComponent(errorPanel);
+        uI.addComponent(errorPanel);
         return null;
     }
 }