Redesign ComboBox filtering, highlighting and selection behaviour.

(#15502, #9369)

Changes:
- When opening the popup, the first suggestion is always highlighted by
default unless adding new items is allowed.
- When filter matches currently selected item, that item will be
highlighted instead of the first item.
- Hitting enter or tab will always select the highlighted item.
- Closing the suggestions list by clicking outside the list no longer
selects an item to prevent accidental selections.

Test changes:
- Extended ComboBoxElement to help test filtering.
- Updated and tweaked ComboBoxResetValueTest,
ComboBoxIdenticalItemsTest and ComboboxScrollableWindowTest.
- Added ComboBoxSelectingTest and
ComboBoxSelectingWithNewItemsAllowedTest.
- Updated some tests that were using keyboard navigation.

Change-Id: Ia7745b624bdb0b1a1bb498157ebcb37bee219d76

2 files changed, 30 insertions, 37 deletions

diff --git a/client/src/com/vaadin/client/ui/VFilterSelect.java b/client/src/com/vaadin/client/ui/VFilterSelect.java
index c0575b1ea5..c99ed49c91 100644
--- a/client/src/com/vaadin/client/ui/VFilterSelect.java
+++ b/client/src/com/vaadin/client/ui/VFilterSelect.java
@@ -813,6 +813,7 @@ public class VFilterSelect extends Composite implements Field, KeyDownHandler,
 
             clearItems();
             final Iterator<FilterSelectSuggestion> it = suggestions.iterator();
+            boolean isFirstIteration = true;
             while (it.hasNext()) {
                 final FilterSelectSuggestion s = it.next();
                 final MenuItem mi = new MenuItem(s.getDisplayString(), true, s);
@@ -821,9 +822,21 @@ public class VFilterSelect extends Composite implements Field, KeyDownHandler,
                 WidgetUtil.sinkOnloadForImages(mi.getElement());
 
                 this.addItem(mi);
-                if (s == currentSuggestion) {
+
+                // By default, first item on the list is always highlighted,
+                // unless adding new items is allowed.
+                if (isFirstIteration && !allowNewItem) {
+                    selectItem(mi);
+                }
+
+                // If the filter matches the current selection, highlight that
+                // instead of the first item.
+                if (tb.getText().equals(s.getReplacementString())
+                        && s == currentSuggestion) {
                     selectItem(mi);
                 }
+
+                isFirstIteration = false;
             }
         }
 
@@ -1178,8 +1191,6 @@ public class VFilterSelect extends Composite implements Field, KeyDownHandler,
     /** For internal use only. May be removed or replaced in the future. */
     public boolean updateSelectionWhenReponseIsReceived = false;
 
-    private boolean tabPressedWhenPopupOpen = false;
-
     /** For internal use only. May be removed or replaced in the future. */
     public boolean initDone = false;
 
@@ -1421,8 +1432,10 @@ public class VFilterSelect extends Composite implements Field, KeyDownHandler,
             return;
         }
         if (!filter.equals(lastFilter)) {
-            // we are on subsequent page and text has changed -> reset page
-            if ("".equals(filter)) {
+            // when filtering, let the server decide the page unless we've
+            // set the filter to empty and explicitly said that we want to see
+            // the results starting from page 0.
+            if ("".equals(filter) && page != 0) {
                 // let server decide
                 page = -1;
             } else {
@@ -1437,7 +1450,6 @@ public class VFilterSelect extends Composite implements Field, KeyDownHandler,
 
         lastFilter = filter;
         currentPage = page;
-
     }
 
     /** For internal use only. May be removed or replaced in the future. */
@@ -1768,16 +1780,12 @@ public class VFilterSelect extends Composite implements Field, KeyDownHandler,
             selectPrevPage();
             event.stopPropagation();
             break;
-        case KeyCodes.KEY_TAB:
-            tabPressedWhenPopupOpen = true;
-            filterOptions(currentPage);
-            // onBlur() takes care of the rest
-            break;
         case KeyCodes.KEY_ESCAPE:
             reset();
             DOM.eventPreventDefault(DOM.eventGetCurrentEvent());
             event.stopPropagation();
             break;
+        case KeyCodes.KEY_TAB:
         case KeyCodes.KEY_ENTER:
             if (suggestionPopup.menu.getKeyboardSelectedItem() == null) {
                 /*
@@ -1785,17 +1793,8 @@ public class VFilterSelect extends Composite implements Field, KeyDownHandler,
                  * text (causes popup to open) and then pressing enter.
                  */
                 if (!allowNewItem) {
-                    /*
-                     * New items are not allowed: If there is only one
-                     * suggestion, select that. If there is more than one
-                     * suggestion Enter key should work as Escape key. Otherwise
-                     * do nothing.
-                     */
-                    if (currentSuggestions.size() == 1) {
-                        onSuggestionSelected(currentSuggestions.get(0));
-                    } else if (currentSuggestions.size() > 1) {
-                        reset();
-                    }
+                    onSuggestionSelected(currentSuggestions
+                            .get(suggestionPopup.menu.getSelectedIndex()));
                 } else {
                     // Handle addition of new items.
                     suggestionPopup.menu.doSelectedItemAction();
@@ -1863,7 +1862,9 @@ public class VFilterSelect extends Composite implements Field, KeyDownHandler,
                 break;
             default:
                 if (textInputEnabled) {
-                    filterOptions(currentPage);
+                    // when filtering, we always want to see the results on the
+                    // first page first.
+                    filterOptions(0);
                 }
                 break;
             }
@@ -2069,19 +2070,6 @@ public class VFilterSelect extends Composite implements Field, KeyDownHandler,
 
         focused = false;
         if (!readonly) {
-            // much of the TAB handling takes place here
-            if (tabPressedWhenPopupOpen) {
-                tabPressedWhenPopupOpen = false;
-                waitingForFilteringResponse = false;
-                suggestionPopup.menu.doSelectedItemAction();
-                suggestionPopup.hide();
-            } else if ((!suggestionPopup.isAttached() && waitingForFilteringResponse)
-                    || suggestionPopup.isJustClosed()) {
-                // typing so fast the popup was never opened, or it's just
-                // closed
-                waitingForFilteringResponse = false;
-                suggestionPopup.menu.doSelectedItemAction();
-            }
             if (selectedOptionKey == null) {
                 setPromptingOn();
             } else if (currentSuggestion != null) {
diff --git a/client/src/com/vaadin/client/ui/combobox/ComboBoxConnector.java b/client/src/com/vaadin/client/ui/combobox/ComboBoxConnector.java
index 461181e18a..8757f46e71 100644
--- a/client/src/com/vaadin/client/ui/combobox/ComboBoxConnector.java
+++ b/client/src/com/vaadin/client/ui/combobox/ComboBoxConnector.java
@@ -166,7 +166,12 @@ public class ComboBoxConnector extends AbstractFieldConnector implements
         ) {
 
             String[] selectedKeys = uidl.getStringArrayVariable("selected");
-            if (selectedKeys.length > 0) {
+
+            // when filtering with empty filter, server sets the selected key
+            // to "", which we don't select here. Otherwise we won't be able to
+            // reset back to the item that was selected before filtering
+            // started.
+            if (selectedKeys.length > 0 && !selectedKeys[0].equals("")) {
                 performSelection(selectedKeys[0]);
             } else {
                 resetSelection();