diff --git a/user/src/com/google/gwt/user/cellview/client/AbstractHasData.java b/user/src/com/google/gwt/user/cellview/client/AbstractHasData.java
index 2923f0d..b33d8de 100644
--- a/user/src/com/google/gwt/user/cellview/client/AbstractHasData.java
+++ b/user/src/com/google/gwt/user/cellview/client/AbstractHasData.java
@@ -72,18 +72,26 @@
       this.hasData = hasData;
     }
 
+    @Override
     public <H extends EventHandler> HandlerRegistration addHandler(H handler,
         Type<H> type) {
       return hasData.addHandler(handler, type);
     }
 
+    @Override
     public void render(SafeHtmlBuilder sb, List<T> values, int start,
         SelectionModel<? super T> selectionModel) {
       hasData.renderRowValues(sb, values, start, selectionModel);
     }
 
+    @Override
     public void replaceAllChildren(List<T> values, SafeHtml html,
-        boolean stealFocus) {
+        boolean stealFocus, boolean contentChanged) {
+      if (!contentChanged) {
+        // Early exit if the content is unchanged.
+        return;
+      }
+
       // Removing elements can fire a blur event, which we ignore.
       hasData.isFocused = hasData.isFocused || stealFocus;
       wasFocused = hasData.isFocused;
@@ -93,6 +101,7 @@
       fireValueChangeEvent();
     }
 
+    @Override
     public void replaceChildren(List<T> values, int start, SafeHtml html,
         boolean stealFocus) {
       // Removing elements can fire a blur event, which we ignore.
@@ -104,9 +113,11 @@
       fireValueChangeEvent();
     }
 
+    @Override
     public void resetFocus() {
       if (wasFocused) {
         CellBasedWidgetImpl.get().resetFocus(new Scheduler.ScheduledCommand() {
+          @Override
           public void execute() {
             if (!hasData.resetFocusOnCell()) {
               Element elem = hasData.getKeyboardSelectedElement();
@@ -119,12 +130,14 @@
       }
     }
 
+    @Override
     public void setKeyboardSelected(int index, boolean seleted,
         boolean stealFocus) {
       hasData.isFocused = hasData.isFocused || stealFocus;
       hasData.setKeyboardSelected(index, seleted, stealFocus);
     }
 
+    @Override
     public void setLoadingState(LoadingState state) {
       hasData.isRefreshing = true;
       hasData.onLoadingStateChanged(state);
@@ -299,6 +312,7 @@
     selectionManagerReg = addCellPreviewHandler(DefaultSelectionEventManager.<T> createDefaultManager());
   }
 
+  @Override
   public HandlerRegistration addCellPreviewHandler(
       CellPreviewEvent.Handler<T> handler) {
     return presenter.addCellPreviewHandler(handler);
@@ -316,11 +330,13 @@
     return presenter.addLoadingStateChangeHandler(handler);
   }
 
+  @Override
   public HandlerRegistration addRangeChangeHandler(
       RangeChangeEvent.Handler handler) {
     return presenter.addRangeChangeHandler(handler);
   }
 
+  @Override
   public HandlerRegistration addRowCountChangeHandler(
       RowCountChangeEvent.Handler handler) {
     return presenter.addRowCountChangeHandler(handler);
@@ -361,14 +377,17 @@
     return getVisibleItems();
   }
 
+  @Override
   public KeyboardPagingPolicy getKeyboardPagingPolicy() {
     return presenter.getKeyboardPagingPolicy();
   }
 
+  @Override
   public KeyboardSelectionPolicy getKeyboardSelectionPolicy() {
     return presenter.getKeyboardSelectionPolicy();
   }
 
+  @Override
   public ProvidesKey<T> getKeyProvider() {
     return presenter.getKeyProvider();
   }
@@ -408,23 +427,28 @@
     return getChildContainer();
   }
 
+  @Override
   public int getRowCount() {
     return presenter.getRowCount();
   }
 
+  @Override
   public SelectionModel<? super T> getSelectionModel() {
     return presenter.getSelectionModel();
   }
 
+  @Override
   public int getTabIndex() {
     return tabIndex;
   }
 
+  @Override
   public T getVisibleItem(int indexOnPage) {
     checkRowBounds(indexOnPage);
     return presenter.getVisibleItem(indexOnPage);
   }
 
+  @Override
   public int getVisibleItemCount() {
     return presenter.getVisibleItemCount();
   }
@@ -435,14 +459,17 @@
    * 
    * @return a List of displayed items
    */
+  @Override
   public List<T> getVisibleItems() {
     return presenter.getVisibleItems();
   }
 
+  @Override
   public Range getVisibleRange() {
     return presenter.getVisibleRange();
   }
 
+  @Override
   public boolean isRowCountExact() {
     return presenter.isRowCountExact();
   }
@@ -536,11 +563,13 @@
    *
    * @see #getAccessKey()
    */
+  @Override
   public void setAccessKey(char key) {
     this.accessKey = key;
     setKeyboardSelected(getKeyboardSelectedRow(), true, false);
   }
 
+  @Override
   public void setFocus(boolean focused) {
     Element elem = getKeyboardSelectedElement();
     if (elem != null) {
@@ -552,10 +581,12 @@
     }
   }
 
+  @Override
   public void setKeyboardPagingPolicy(KeyboardPagingPolicy policy) {
     presenter.setKeyboardPagingPolicy(policy);
   }
 
+  @Override
   public void setKeyboardSelectionPolicy(KeyboardSelectionPolicy policy) {
     presenter.setKeyboardSelectionPolicy(policy);
   }
@@ -584,10 +615,12 @@
     setVisibleRange(pageStart, getPageSize());
   }
 
+  @Override
   public final void setRowCount(int count) {
     setRowCount(count, true);
   }
 
+  @Override
   public void setRowCount(int size, boolean isExact) {
     presenter.setRowCount(size, isExact);
   }
@@ -611,6 +644,7 @@
     setRowData(0, values);
   }
 
+  @Override
   public void setRowData(int start, List<? extends T> values) {
     presenter.setRowData(start, values);
   }
@@ -633,6 +667,7 @@
    *      com.google.gwt.view.client.CellPreviewEvent.Handler)
    * @see #getSelectionModel()
    */
+  @Override
   public void setSelectionModel(SelectionModel<? super T> selectionModel) {
     presenter.setSelectionModel(selectionModel);
   }
@@ -662,19 +697,23 @@
     setSelectionModel(selectionModel);
   }
 
+  @Override
   public void setTabIndex(int index) {
     this.tabIndex = index;
     setKeyboardSelected(getKeyboardSelectedRow(), true, false);
   }
 
+  @Override
   public final void setVisibleRange(int start, int length) {
     setVisibleRange(new Range(start, length));
   }
 
+  @Override
   public void setVisibleRange(Range range) {
     presenter.setVisibleRange(range);
   }
 
+  @Override
   public void setVisibleRangeAndClearData(Range range,
       boolean forceRangeChangeEvent) {
     presenter.setVisibleRangeAndClearData(range, forceRangeChangeEvent);
diff --git a/user/src/com/google/gwt/user/cellview/client/CellTreeNodeView.java b/user/src/com/google/gwt/user/cellview/client/CellTreeNodeView.java
index 04e8c8a..b7befb3 100644
--- a/user/src/com/google/gwt/user/cellview/client/CellTreeNodeView.java
+++ b/user/src/com/google/gwt/user/cellview/client/CellTreeNodeView.java
@@ -192,7 +192,7 @@
 
       @Override
       public void replaceAllChildren(List<C> values, SafeHtml html,
-          boolean stealFocus) {
+          boolean stealFocus, boolean contentChanged) {
         // Hide the child container so we can animate it.
         if (nodeView.tree.isAnimationEnabled()) {
           nodeView.ensureAnimationFrame().getStyle().setDisplay(Display.NONE);
@@ -201,7 +201,9 @@
         // Replace the child nodes.
         nodeView.tree.isRefreshing = true;
         Map<Object, CellTreeNodeView<?>> savedViews = saveChildState(values, 0);
-        AbstractHasData.replaceAllChildren(nodeView.tree, childContainer, html);
+        if (contentChanged) {
+          AbstractHasData.replaceAllChildren(nodeView.tree, childContainer, html);
+        }
         nodeView.tree.isRefreshing = false;
 
         // Trim the list of children.
diff --git a/user/src/com/google/gwt/user/cellview/client/HasDataPresenter.java b/user/src/com/google/gwt/user/cellview/client/HasDataPresenter.java
index 74b81d8..c3d219a 100644
--- a/user/src/com/google/gwt/user/cellview/client/HasDataPresenter.java
+++ b/user/src/com/google/gwt/user/cellview/client/HasDataPresenter.java
@@ -66,8 +66,7 @@
  * 
  * @param <T> the data type of items in the list
  */
-class HasDataPresenter<T> implements HasData<T>, HasKeyProvider<T>,
-    HasKeyboardPagingPolicy {
+class HasDataPresenter<T> implements HasData<T>, HasKeyProvider<T>, HasKeyboardPagingPolicy {
 
   /**
    * An iterator over DOM elements.
@@ -96,8 +95,7 @@
      * @param handler the handler to add
      * @param type the event type
      */
-    <H extends EventHandler> HandlerRegistration addHandler(final H handler,
-        GwtEvent.Type<H> type);
+    <H extends EventHandler> HandlerRegistration addHandler(final H handler, GwtEvent.Type<H> type);
 
     /**
      * Construct the HTML that represents the list of values, taking the
@@ -117,8 +115,12 @@
      * @param values the values of the new children
      * @param html the html to render in the child
      * @param stealFocus true if the row should steal focus, false if not
+     * @param contentChanged indicates whether or not the content has changed
+     *          since the last call. If the content has not changed, widgets can
+     *          choose not to rerender themselves
      */
-    void replaceAllChildren(List<T> values, SafeHtml html, boolean stealFocus);
+    void replaceAllChildren(List<T> values, SafeHtml html, boolean stealFocus,
+        boolean contentChanged);
 
     /**
      * Convert the specified HTML into DOM elements and replace the existing
@@ -131,8 +133,7 @@
      * @param html the HTML to convert
      * @param stealFocus true if the row should steal focus, false if not
      */
-    void replaceChildren(List<T> values, int start, SafeHtml html,
-        boolean stealFocus);
+    void replaceChildren(List<T> values, int start, SafeHtml html, boolean stealFocus);
 
     /**
      * Re-establish focus on an element within the view if the view already had
@@ -463,8 +464,7 @@
    * @param view the view implementation
    * @param pageSize the default page size
    */
-  public HasDataPresenter(HasData<T> display, View<T> view, int pageSize,
-      ProvidesKey<T> keyProvider) {
+  public HasDataPresenter(HasData<T> display, View<T> view, int pageSize, ProvidesKey<T> keyProvider) {
     this.display = display;
     this.view = view;
     this.keyProvider = keyProvider;
@@ -472,25 +472,21 @@
   }
 
   @Override
-  public HandlerRegistration addCellPreviewHandler(
-      CellPreviewEvent.Handler<T> handler) {
+  public HandlerRegistration addCellPreviewHandler(CellPreviewEvent.Handler<T> handler) {
     return view.addHandler(handler, CellPreviewEvent.getType());
   }
 
-  public HandlerRegistration addLoadingStateChangeHandler(
-      LoadingStateChangeEvent.Handler handler) {
+  public HandlerRegistration addLoadingStateChangeHandler(LoadingStateChangeEvent.Handler handler) {
     return view.addHandler(handler, LoadingStateChangeEvent.TYPE);
   }
 
   @Override
-  public HandlerRegistration addRangeChangeHandler(
-      RangeChangeEvent.Handler handler) {
+  public HandlerRegistration addRangeChangeHandler(RangeChangeEvent.Handler handler) {
     return view.addHandler(handler, RangeChangeEvent.getType());
   }
 
   @Override
-  public HandlerRegistration addRowCountChangeHandler(
-      RowCountChangeEvent.Handler handler) {
+  public HandlerRegistration addRowCountChangeHandler(RowCountChangeEvent.Handler handler) {
     return view.addHandler(handler, RowCountChangeEvent.getType());
   }
 
@@ -559,8 +555,8 @@
    * @return the row index, or -1 if disabled
    */
   public int getKeyboardSelectedRow() {
-    return KeyboardSelectionPolicy.DISABLED == keyboardSelectionPolicy ? -1
-        : getCurrentState().getKeyboardSelectedRow();
+    return KeyboardSelectionPolicy.DISABLED == keyboardSelectionPolicy ? -1 : getCurrentState()
+        .getKeyboardSelectedRow();
   }
 
   /**
@@ -571,8 +567,8 @@
    * @return the row index, or -1 if disabled
    */
   public int getKeyboardSelectedRowInView() {
-    return KeyboardSelectionPolicy.DISABLED == keyboardSelectionPolicy ? -1
-        : state.getKeyboardSelectedRow();
+    return KeyboardSelectionPolicy.DISABLED == keyboardSelectionPolicy ? -1 : state
+        .getKeyboardSelectedRow();
   }
 
   /**
@@ -581,8 +577,8 @@
    * @return the value, or null if a value was not selected
    */
   public T getKeyboardSelectedRowValue() {
-    return KeyboardSelectionPolicy.DISABLED == keyboardSelectionPolicy ? null
-        : getCurrentState().getKeyboardSelectedRowValue();
+    return KeyboardSelectionPolicy.DISABLED == keyboardSelectionPolicy ? null : getCurrentState()
+        .getKeyboardSelectedRowValue();
   }
 
   @Override
@@ -727,8 +723,7 @@
       // 0th index of next page.
       setKeyboardSelectedRow(getPageSize(), true, false);
     } else if (KeyboardPagingPolicy.INCREASE_RANGE == keyboardPagingPolicy) {
-      setKeyboardSelectedRow(getKeyboardSelectedRow() + PAGE_INCREMENT, true,
-          false);
+      setKeyboardSelectedRow(getKeyboardSelectedRow() + PAGE_INCREMENT, true, false);
     }
   }
 
@@ -749,8 +744,7 @@
       // 0th index of previous page.
       setKeyboardSelectedRow(-getPageSize(), true, false);
     } else if (KeyboardPagingPolicy.INCREASE_RANGE == keyboardPagingPolicy) {
-      setKeyboardSelectedRow(getKeyboardSelectedRow() - PAGE_INCREMENT, true,
-          false);
+      setKeyboardSelectedRow(getKeyboardSelectedRow() - PAGE_INCREMENT, true, false);
     }
   }
 
@@ -777,8 +771,7 @@
    * @param stealFocus true to steal focus
    * @param forceUpdate force the update even if the row didn't change
    */
-  public void setKeyboardSelectedRow(int index, boolean stealFocus,
-      boolean forceUpdate) {
+  public void setKeyboardSelectedRow(int index, boolean stealFocus, boolean forceUpdate) {
     // Early exit if disabled.
     if (KeyboardSelectionPolicy.DISABLED == keyboardSelectionPolicy) {
       return;
@@ -791,8 +784,7 @@
      * Early exit if the keyboard selected row has not changed and the keyboard
      * selected value is already set.
      */
-    if (!forceUpdate && getKeyboardSelectedRow() == index
-        && getKeyboardSelectedRowValue() != null) {
+    if (!forceUpdate && getKeyboardSelectedRow() == index && getKeyboardSelectedRowValue() != null) {
       return;
     }
 
@@ -818,8 +810,8 @@
     pending.keyboardSelectedRowChanged = true;
     if (index >= 0 && index < pageSize) {
       pending.keyboardSelectedRow = index;
-      pending.keyboardSelectedRowValue = index < pending.getRowDataSize()
-          ? ensurePendingState().getRowDataValue(index) : null;
+      pending.keyboardSelectedRowValue =
+          index < pending.getRowDataSize() ? ensurePendingState().getRowDataValue(index) : null;
       pending.keyboardStealFocus = stealFocus;
       return;
     } else if (KeyboardPagingPolicy.CHANGE_PAGE == keyboardPagingPolicy) {
@@ -917,8 +909,7 @@
 
     // Create placeholders up to the specified index.
     PendingState<T> pending = ensurePendingState();
-    int cacheOffset = Math.max(0, boundedStart - pageStart
-        - getVisibleItemCount());
+    int cacheOffset = Math.max(0, boundedStart - pageStart - getVisibleItemCount());
     for (int i = 0; i < cacheOffset; i++) {
       pending.rowData.add(null);
     }
@@ -950,13 +941,14 @@
     // Set the new selection model.
     this.selectionModel = selectionModel;
     if (selectionModel != null) {
-      selectionHandler = selectionModel.addSelectionChangeHandler(new SelectionChangeEvent.Handler() {
-        @Override
-        public void onSelectionChange(SelectionChangeEvent event) {
-          // Ensure that we resolve selection.
-          ensurePendingState();
-        }
-      });
+      selectionHandler =
+          selectionModel.addSelectionChangeHandler(new SelectionChangeEvent.Handler() {
+            @Override
+            public void onSelectionChange(SelectionChangeEvent event) {
+              // Ensure that we resolve selection.
+              ensurePendingState();
+            }
+          });
     }
 
     // Update the current selection state based on the new model.
@@ -979,8 +971,7 @@
   }
 
   @Override
-  public void setVisibleRangeAndClearData(Range range,
-      boolean forceRangeChangeEvent) {
+  public void setVisibleRangeAndClearData(Range range, boolean forceRangeChangeEvent) {
     setVisibleRange(range, true, forceRangeChangeEvent);
   }
 
@@ -1009,8 +1000,7 @@
    * @param modifiedRows the indexes of modified rows
    * @return up to two ranges that encompass the modified rows
    */
-  List<Range> calculateModifiedRanges(TreeSet<Integer> modifiedRows,
-      int pageStart, int pageEnd) {
+  List<Range> calculateModifiedRanges(TreeSet<Integer> modifiedRows, int pageStart, int pageEnd) {
     int rangeStart0 = -1;
     int rangeEnd0 = -1;
     int rangeStart1 = -1;
@@ -1157,8 +1147,7 @@
    * @return the key
    */
   private Object getRowValueKey(T rowValue) {
-    return (keyProvider == null || rowValue == null) ? rowValue
-        : keyProvider.getKey(rowValue);
+    return (keyProvider == null || rowValue == null) ? rowValue : keyProvider.getKey(rowValue);
   }
 
   /**
@@ -1195,8 +1184,7 @@
       throw new IllegalStateException(
           "The Cell Widget is attempting to render itself within the render "
               + "loop. This usually happens when your render code modifies the "
-              + "state of the Cell Widget then accesses data or elements "
-              + "within the Widget.");
+              + "state of the Cell Widget then accesses data or elements " + "within the Widget.");
     }
     isResolvingState = true;
 
@@ -1216,25 +1204,26 @@
      * If the row value exists in multiple places, use the closest index. If the
      * row value not longer exists, use the current index.
      */
-    pending.keyboardSelectedRow = Math.max(0,
-        Math.min(pending.keyboardSelectedRow, rowDataCount - 1));
+    pending.keyboardSelectedRow =
+        Math.max(0, Math.min(pending.keyboardSelectedRow, rowDataCount - 1));
     if (KeyboardSelectionPolicy.DISABLED == keyboardSelectionPolicy) {
       // Clear the keyboard selected state.
       pending.keyboardSelectedRow = 0;
       pending.keyboardSelectedRowValue = null;
     } else if (pending.keyboardSelectedRowChanged) {
       // Choose the row value based on the index.
-      pending.keyboardSelectedRowValue = rowDataCount > 0
-          ? pending.getRowDataValue(pending.keyboardSelectedRow) : null;
+      pending.keyboardSelectedRowValue =
+          rowDataCount > 0 ? pending.getRowDataValue(pending.keyboardSelectedRow) : null;
     } else if (pending.keyboardSelectedRowValue != null) {
       // Choose the index based on the row value.
-      int bestMatchIndex = findIndexOfBestMatch(pending,
-          pending.keyboardSelectedRowValue, pending.keyboardSelectedRow);
+      int bestMatchIndex =
+          findIndexOfBestMatch(pending, pending.keyboardSelectedRowValue,
+              pending.keyboardSelectedRow);
       if (bestMatchIndex >= 0) {
         // A match was found.
         pending.keyboardSelectedRow = bestMatchIndex;
-        pending.keyboardSelectedRowValue = rowDataCount > 0
-            ? pending.getRowDataValue(pending.keyboardSelectedRow) : null;
+        pending.keyboardSelectedRowValue =
+            rowDataCount > 0 ? pending.getRowDataValue(pending.keyboardSelectedRow) : null;
       } else {
         // No match was found, so reset to 0.
         pending.keyboardSelectedRow = 0;
@@ -1253,8 +1242,8 @@
           && selectionModel != null && pending.viewTouched) {
         T oldValue = oldState.getSelectedValue();
         Object oldKey = getRowValueKey(oldValue);
-        T newValue = rowDataCount > 0
-            ? pending.getRowDataValue(pending.getKeyboardSelectedRow()) : null;
+        T newValue =
+            rowDataCount > 0 ? pending.getRowDataValue(pending.getKeyboardSelectedRow()) : null;
         Object newKey = getRowValueKey(newValue);
         /*
          * Do not deselect the old value unless we have a new value to select,
@@ -1264,10 +1253,10 @@
         if (newKey != null && !newKey.equals(oldKey)) {
           // Check both values for selection before setting selection, or the
           // selection model may resolve state early.
-          boolean oldValueWasSelected = (oldValue == null) ? false
-              : selectionModel.isSelected(oldValue);
-          boolean newValueWasSelected = (newValue == null) ? false
-              : selectionModel.isSelected(newValue);
+          boolean oldValueWasSelected =
+              (oldValue == null) ? false : selectionModel.isSelected(oldValue);
+          boolean newValueWasSelected =
+              (newValue == null) ? false : selectionModel.isSelected(newValue);
 
           // Deselect the old value.
           if (oldValueWasSelected) {
@@ -1288,9 +1277,10 @@
     }
 
     // If the keyboard row changes, add it to the modified set.
-    boolean keyboardRowChanged = pending.keyboardSelectedRowChanged
-        || (oldState.getKeyboardSelectedRow() != pending.keyboardSelectedRow)
-        || (oldState.getKeyboardSelectedRowValue() == null && pending.keyboardSelectedRowValue != null);
+    boolean keyboardRowChanged =
+        pending.keyboardSelectedRowChanged
+            || (oldState.getKeyboardSelectedRow() != pending.keyboardSelectedRow)
+            || (oldState.getKeyboardSelectedRowValue() == null && pending.keyboardSelectedRowValue != null);
 
     /*
      * Resolve selection. Check the selection status of all row values in the
@@ -1301,7 +1291,8 @@
     for (int i = pageStart; i < pageStart + rowDataCount; i++) {
       // Check the new selection state.
       T rowValue = pending.getRowDataValue(i - pageStart);
-      boolean isSelected = (rowValue != null && selectionModel != null && selectionModel.isSelected(rowValue));
+      boolean isSelected =
+          (rowValue != null && selectionModel != null && selectionModel.isSelected(rowValue));
 
       // Compare to the old selection state.
       boolean wasSelected = oldState.isRowSelected(i);
@@ -1350,8 +1341,7 @@
     }
 
     // Calculate the modified ranges.
-    List<Range> modifiedRanges = calculateModifiedRanges(modifiedRows,
-        pageStart, pageEnd);
+    List<Range> modifiedRanges = calculateModifiedRanges(modifiedRows, pageStart, pageEnd);
     Range range0 = modifiedRanges.size() > 0 ? modifiedRanges.get(0) : null;
     Range range1 = modifiedRanges.size() > 1 ? modifiedRanges.get(1) : null;
     int replaceDiff = 0; // The total number of rows to replace.
@@ -1372,13 +1362,11 @@
     } else if (rowDataCount < oldRowDataCount) {
       // Redraw if we have trimmed the row data.
       redrawRequired = true;
-    } else if (range1 == null && range0 != null
-        && range0.getStart() == pageStart
+    } else if (range1 == null && range0 != null && range0.getStart() == pageStart
         && (replaceDiff >= oldRowDataCount || replaceDiff > oldPageSize)) {
       // Redraw if the new data completely overlaps the old data.
       redrawRequired = true;
-    } else if (replaceDiff >= REDRAW_MINIMUM
-        && replaceDiff > REDRAW_THRESHOLD * oldRowDataCount) {
+    } else if (replaceDiff >= REDRAW_MINIMUM && replaceDiff > REDRAW_THRESHOLD * oldRowDataCount) {
       /*
        * Redraw if the number of modified rows represents a large portion of the
        * view, defined as greater than 30% of the rows (minimum of 5).
@@ -1405,11 +1393,10 @@
         SafeHtmlBuilder sb = new SafeHtmlBuilder();
         view.render(sb, pending.rowData, pending.pageStart, selectionModel);
         SafeHtml newContents = sb.toSafeHtml();
-        if (!newContents.equals(lastContents)) {
-          lastContents = newContents;
-          view.replaceAllChildren(pending.rowData, newContents,
-              pending.keyboardStealFocus);
-        }
+        boolean contentChanged = !newContents.equals(lastContents);
+        lastContents = newContents;
+        view.replaceAllChildren(pending.rowData, newContents, pending.keyboardStealFocus,
+            contentChanged);
         view.resetFocus();
       } else if (range0 != null) {
         // Replace specific rows.
@@ -1420,11 +1407,9 @@
           int absStart = range0.getStart();
           int relStart = absStart - pageStart;
           SafeHtmlBuilder sb = new SafeHtmlBuilder();
-          List<T> replaceValues = pending.rowData.subList(relStart, relStart
-              + range0.getLength());
+          List<T> replaceValues = pending.rowData.subList(relStart, relStart + range0.getLength());
           view.render(sb, replaceValues, absStart, selectionModel);
-          view.replaceChildren(replaceValues, relStart, sb.toSafeHtml(),
-              pending.keyboardStealFocus);
+          view.replaceChildren(replaceValues, relStart, sb.toSafeHtml(), pending.keyboardStealFocus);
         }
 
         // Replace range1 if it exists.
@@ -1432,11 +1417,9 @@
           int absStart = range1.getStart();
           int relStart = absStart - pageStart;
           SafeHtmlBuilder sb = new SafeHtmlBuilder();
-          List<T> replaceValues = pending.rowData.subList(relStart, relStart
-              + range1.getLength());
+          List<T> replaceValues = pending.rowData.subList(relStart, relStart + range1.getLength());
           view.render(sb, replaceValues, absStart, selectionModel);
-          view.replaceChildren(replaceValues, relStart, sb.toSafeHtml(),
-              pending.keyboardStealFocus);
+          view.replaceChildren(replaceValues, relStart, sb.toSafeHtml(), pending.keyboardStealFocus);
         }
 
         view.resetFocus();
@@ -1451,8 +1434,7 @@
         // Select the new keyboard row.
         int newSelectedRow = pending.getKeyboardSelectedRow();
         if (newSelectedRow >= 0 && newSelectedRow < rowDataCount) {
-          view.setKeyboardSelected(newSelectedRow, true,
-              pending.keyboardStealFocus);
+          view.setKeyboardSelected(newSelectedRow, true, pending.keyboardStealFocus);
         }
       }
     } catch (Error e) {
@@ -1476,8 +1458,7 @@
    * @param clearData true to clear all data
    * @param forceRangeChangeEvent true to force a {@link RangeChangeEvent}
    */
-  private void setVisibleRange(Range range, boolean clearData,
-      boolean forceRangeChangeEvent) {
+  private void setVisibleRange(Range range, boolean clearData, boolean forceRangeChangeEvent) {
     final int start = range.getStart();
     final int length = range.getLength();
     if (start < 0) {
@@ -1555,8 +1536,7 @@
    */
   private void updateCachedData() {
     int pageStart = getPageStart();
-    int expectedLastIndex = Math.max(0,
-        Math.min(getPageSize(), getRowCount() - pageStart));
+    int expectedLastIndex = Math.max(0, Math.min(getPageSize(), getRowCount() - pageStart));
     int lastIndex = getVisibleItemCount() - 1;
     while (lastIndex >= expectedLastIndex) {
       ensurePendingState().rowData.remove(lastIndex);
diff --git a/user/test/com/google/gwt/user/cellview/client/CellTreeTest.java b/user/test/com/google/gwt/user/cellview/client/CellTreeTest.java
index 05b6ae4..222888d 100644
--- a/user/test/com/google/gwt/user/cellview/client/CellTreeTest.java
+++ b/user/test/com/google/gwt/user/cellview/client/CellTreeTest.java
@@ -1,12 +1,12 @@
 /*
  * Copyright 2010 Google Inc.
- *
+ * 
  * 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
@@ -15,10 +15,16 @@
  */
 package com.google.gwt.user.cellview.client;
 
+import com.google.gwt.cell.client.AbstractCell;
 import com.google.gwt.cell.client.TextCell;
+import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
+import com.google.gwt.user.client.ui.RootPanel;
 import com.google.gwt.view.client.ListDataProvider;
 import com.google.gwt.view.client.TreeViewModel;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * Tests for {@link CellTree}.
  */
@@ -47,7 +53,7 @@
     // Create the tree.
     CellTree tree = createAbstractCellTree(model, null);
     tree.rootNode.listView.presenter.flush();
-    
+
     // Refresh the empty list.
     provider.refresh();
     provider.flush();
@@ -55,6 +61,70 @@
   }
 
   /**
+   * Test that CellTree handles rendering the same content, but with a different
+   * underlying value.
+   */
+  public void testRenderSameContent() {
+    final AbstractCell<Integer> intCell = new AbstractCell<Integer>() {
+      @Override
+      public void render(Context context, Integer value, SafeHtmlBuilder sb) {
+        sb.append(value % 10); // Render the units digit only.
+      }
+    };
+
+    // Create a data provider for the root node.
+    final ListDataProvider<Integer> root = new ListDataProvider<Integer>();
+    for (int i = 0; i < 9; i++) {
+      root.getList().add(i);
+    }
+
+    TreeViewModel model = new TreeViewModel() {
+      @Override
+      public NodeInfo<?> getNodeInfo(Object value) {
+        if (value == null) {
+          // Return the root node.
+          return new DefaultNodeInfo<Integer>(root, intCell);
+        } else {
+          // Return a child node.
+          return new DefaultNodeInfo<String>(new ListDataProvider<String>(), new TextCell());
+        }
+      }
+
+      @Override
+      public boolean isLeaf(Object value) {
+        return false;
+      }
+    };
+
+    CellTree tree = createAbstractCellTree(model, null);
+    RootPanel.get().add(tree);
+    tree.rootNode.listView.presenter.flush();
+
+    // Open the first child.
+    TreeNode rootNode = tree.getRootTreeNode();
+    assertEquals(1, rootNode.getChildValue(1));
+    TreeNode child1 = rootNode.setChildOpen(1, true);
+    assertFalse(child1.isDestroyed());
+    assertTrue(rootNode.isChildOpen(1));
+
+    // Replace all values in the list.
+    List<Integer> oldData = root.getList();
+    List<Integer> newData = new ArrayList<Integer>();
+    for (int l : oldData) {
+      newData.add(l + 100); // renders the same as the current value.
+    }
+    root.setList(newData);
+    root.flush();
+    tree.rootNode.listView.presenter.flush();
+
+    // Child1 is closed and destroyed.
+    assertFalse(rootNode.isChildOpen(1));
+    assertTrue(child1.isDestroyed());
+
+    RootPanel.get().remove(tree);
+  }
+
+  /**
    * Test that replacing a subset of children updates both the TreeNode value
    * and the underlying DOM correctly.
    */
@@ -80,7 +150,7 @@
     assertEquals("ab", a.getChildValue(1));
     assertEquals("new", newNode.getValue());
     assertEquals("newc", newNode.getChildValue(2));
-    
+
     // Check the underlying DOM values.
     CellTreeNodeView<?> aImpl = cellTree.rootNode.getChildNode(0);
     CellTreeNodeView<?> newNodeImpl = cellTree.rootNode.getChildNode(1);
@@ -106,8 +176,7 @@
   }
 
   @Override
-  protected <T> CellTree createAbstractCellTree(
-      TreeViewModel model, T rootValue) {
+  protected <T> CellTree createAbstractCellTree(TreeViewModel model, T rootValue) {
     return new CellTree(model, rootValue);
   }
 }
diff --git a/user/test/com/google/gwt/user/cellview/client/HasDataPresenterTest.java b/user/test/com/google/gwt/user/cellview/client/HasDataPresenterTest.java
index 358a5c9..e287e41 100644
--- a/user/test/com/google/gwt/user/cellview/client/HasDataPresenterTest.java
+++ b/user/test/com/google/gwt/user/cellview/client/HasDataPresenterTest.java
@@ -68,6 +68,7 @@
       eventFired = false;
     }
 
+    @Override
     public void onSelectionChange(SelectionChangeEvent event) {
       assertFalse(eventFired);
       eventFired = true;
@@ -105,8 +106,10 @@
     private final List<SafeHtml> lastHtml = new ArrayList<SafeHtml>();
     private LoadingState loadingState;
     private boolean replaceAllChildrenCalled;
+    private boolean replaceAllChildrenCalledWithSameContent;
     private boolean replaceChildrenCalled;
 
+    @Override
     public <H extends EventHandler> HandlerRegistration addHandler(H handler,
         Type<H> type) {
       throw new UnsupportedOperationException();
@@ -149,6 +152,12 @@
       replaceAllChildrenCalled = false;
     }
 
+    public void assertReplaceAllChildrenCalled(boolean expected, boolean sameContent) {
+      assertReplaceAllChildrenCalled(expected);
+      assertEquals(sameContent, replaceAllChildrenCalledWithSameContent);
+      replaceAllChildrenCalledWithSameContent = false;
+    }
+
     public void assertReplaceChildrenCalled(boolean expected) {
       assertEquals(expected, replaceChildrenCalled);
       replaceChildrenCalled = false;
@@ -158,19 +167,23 @@
       return childCount;
     }
 
+    @Override
     public void render(SafeHtmlBuilder sb, List<T> values, int start,
         SelectionModel<? super T> selectionModel) {
       sb.appendHtmlConstant("start=").append(start);
       sb.appendHtmlConstant(",size=").append(values.size());
     }
 
+    @Override
     public void replaceAllChildren(List<T> values, SafeHtml html,
-        boolean stealFocus) {
+        boolean stealFocus, boolean contentChanged) {
+      replaceAllChildrenCalledWithSameContent = !contentChanged;
       childCount = values.size();
       replaceAllChildrenCalled = true;
       lastHtml.add(html);
     }
 
+    @Override
     public void replaceChildren(List<T> values, int start, SafeHtml html,
         boolean stealFocus) {
       childCount = Math.max(childCount, start + values.size());
@@ -178,15 +191,18 @@
       lastHtml.add(html);
     }
 
+    @Override
     public void resetFocus() {
     }
 
+    @Override
     public void setKeyboardSelected(int index, boolean selected,
         boolean stealFocus) {
       keyboardSelectedRow.add(index);
       keyboardSelectedRowState.add(selected);
     }
 
+    @Override
     public void setLoadingState(LoadingState state) {
       this.loadingState = state;
     }
@@ -280,21 +296,26 @@
    */
   public void testBadViewSelectionModel() {
     SelectionModel<String> badModel = new SelectionModel<String>() {
+      @Override
       public void fireEvent(GwtEvent<?> event) {
       }
 
+      @Override
       public Object getKey(String item) {
         return null;
       }
 
+      @Override
       public HandlerRegistration addSelectionChangeHandler(Handler handler) {
         return null;
       }
 
+      @Override
       public boolean isSelected(String object) {
         throw new NullPointerException();
       }
 
+      @Override
       public void setSelected(String object, boolean selected) {
         throw new NullPointerException();
       }
@@ -338,7 +359,7 @@
     MockView<String> badView = new MockView<String>() {
       @Override
       public void replaceAllChildren(List<String> values, SafeHtml html,
-          boolean stealFocus) {
+          boolean stealFocus, boolean contentChanged) {
         throw new NullPointerException();
       }
 
@@ -889,6 +910,7 @@
     // The pending command is scheduled. Wait for it to execute.
     delayTestFinish(5000);
     Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
+      @Override
       public void execute() {
         assertFalse(presenter.hasPendingState());
         view.assertReplaceAllChildrenCalled(true);
@@ -1536,7 +1558,7 @@
     presenter.setVisibleRange(new Range(0, 10));
     presenter.setRowData(0, createData(0, 10));
     presenter.flush();
-    view.assertReplaceAllChildrenCalled(true);
+    view.assertReplaceAllChildrenCalled(true, false);
     view.assertReplaceChildrenCalled(false);
     view.assertLastHtml("start=0,size=10");
     view.assertLoadingState(LoadingState.LOADED);
@@ -1544,9 +1566,9 @@
     // Set the same data over the entire range.
     presenter.setRowData(0, createData(0, 10));
     presenter.flush();
-    view.assertReplaceAllChildrenCalled(false);
+    view.assertReplaceAllChildrenCalled(true, true);
     view.assertReplaceChildrenCalled(false);
-    view.assertLastHtml(null);
+    view.assertLastHtml("start=0,size=10");
     view.assertLoadingState(LoadingState.LOADED);
   }
 
@@ -1669,6 +1691,7 @@
     // Add a range change handler.
     final List<Range> events = new ArrayList<Range>();
     listView.addRangeChangeHandler(new RangeChangeEvent.Handler() {
+      @Override
       public void onRangeChange(RangeChangeEvent event) {
         events.add(event.getNewRange());
       }
@@ -1707,6 +1730,7 @@
     // Add a range change handler.
     final List<Range> events = new ArrayList<Range>();
     listView.addRangeChangeHandler(new RangeChangeEvent.Handler() {
+      @Override
       public void onRangeChange(RangeChangeEvent event) {
         events.add(event.getNewRange());
       }
@@ -1744,6 +1768,7 @@
     // Add a range change handler.
     final List<Range> events = new ArrayList<Range>();
     listView.addRangeChangeHandler(new RangeChangeEvent.Handler() {
+      @Override
       public void onRangeChange(RangeChangeEvent event) {
         events.add(event.getNewRange());
       }