1 files changed, 21 insertions, 6 deletions
diff --git a/src/com/vaadin/event/dd/acceptcriteria/SourceIs.java b/src/com/vaadin/event/dd/acceptcriteria/SourceIs.java
index 8562bc70ec..0d29e9a327 100644
--- a/src/com/vaadin/event/dd/acceptcriteria/SourceIs.java
+++ b/src/com/vaadin/event/dd/acceptcriteria/SourceIs.java
@@ -6,6 +6,9 @@
  */
 package com.vaadin.event.dd.acceptcriteria;
 
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
 import com.vaadin.event.TransferableImpl;
 import com.vaadin.event.dd.DragAndDropEvent;
 import com.vaadin.terminal.PaintException;
@@ -22,27 +25,39 @@ import com.vaadin.ui.Component;
 @SuppressWarnings("serial")
 @ClientCriterion(VDragSourceIs.class)
 public class SourceIs extends ClientSideCriterion {
+    private static final Logger logger = Logger.getLogger(SourceIs.class
+            .getName());
 
-    private Component[] component;
+    private Component[] components;
 
     public SourceIs(Component... component) {
-        this.component = component;
+        components = component;
     }
 
     @Override
     public void paintContent(PaintTarget target) throws PaintException {
         super.paintContent(target);
-        target.addAttribute("c", component.length);
-        for (int i = 0; i < component.length; i++) {
-            target.addAttribute("component" + i, component[i]);
+        int paintedComponents = 0;
+        for (int i = 0; i < components.length; i++) {
+            Component c = components[i];
+            if (c.getApplication() != null) {
+                target.addAttribute("component" + paintedComponents++, c);
+            } else {
+                logger.log(
+                        Level.WARNING,
+                        "SourceIs component {0} at index {1} is not attached to the component hierachy and will thus be ignored",
+                        new Object[] { c.getClass().getName(),
+                                Integer.valueOf(i) });
+            }
         }
+        target.addAttribute("c", paintedComponents);
     }
 
     public boolean accept(DragAndDropEvent dragEvent) {
         if (dragEvent.getTransferable() instanceof TransferableImpl) {
             Component sourceComponent = ((TransferableImpl) dragEvent
                     .getTransferable()).getSourceComponent();
-            for (Component c : component) {
+            for (Component c : components) {
                 if (c == sourceComponent) {
                     return true;
                 }