diff --git a/mozilla/layout/xul/base/src/grid/nsGridLayout2.cpp b/mozilla/layout/xul/base/src/grid/nsGridLayout2.cpp
index 142b3cffe05..157e669fe87 100644
--- a/mozilla/layout/xul/base/src/grid/nsGridLayout2.cpp
+++ b/mozilla/layout/xul/base/src/grid/nsGridLayout2.cpp
@@ -285,6 +285,39 @@ nsGridLayout2::GetRowCount(PRInt32& aRowCount)
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsGridLayout2::ChildrenInserted(nsIBox* aBox, nsBoxLayoutState& aState,
+                                nsIBox* aPrevBox, nsIBox* aChildList)
+{
+  mGrid.NeedsRebuild(aState);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsGridLayout2::ChildrenAppended(nsIBox* aBox, nsBoxLayoutState& aState,
+                                nsIBox* aChildList)
+{
+  mGrid.NeedsRebuild(aState);
+  return NS_OK;
+}
+
+
+NS_IMETHODIMP
+nsGridLayout2::ChildrenRemoved(nsIBox* aBox, nsBoxLayoutState& aState,
+                               nsIBox* aChildList)
+{
+  mGrid.NeedsRebuild(aState);
+  return NS_OK;
+}
+
+
+NS_IMETHODIMP
+nsGridLayout2::ChildrenSet(nsIBox* aBox, nsBoxLayoutState& aState,
+                           nsIBox* aChildList)
+{
+  mGrid.NeedsRebuild(aState);
+  return NS_OK;
+}
 
 NS_IMPL_ADDREF_INHERITED(nsGridLayout2, nsStackLayout)
 NS_IMPL_RELEASE_INHERITED(nsGridLayout2, nsStackLayout)
diff --git a/mozilla/layout/xul/base/src/grid/nsGridLayout2.h b/mozilla/layout/xul/base/src/grid/nsGridLayout2.h
index a4d9fffccbe..bdb85adde25 100644
--- a/mozilla/layout/xul/base/src/grid/nsGridLayout2.h
+++ b/mozilla/layout/xul/base/src/grid/nsGridLayout2.h
@@ -75,7 +75,14 @@ public:
   NS_IMETHOD BuildRows(nsIBox* aBox, nsGridRow* aRows, PRInt32* aCount);
   NS_IMETHOD GetTotalMargin(nsIBox* aBox, nsMargin& aMargin, PRBool aIsHorizontal);
   NS_IMETHOD GetRowCount(PRInt32& aRowCount);
-
+  NS_IMETHOD ChildrenInserted(nsIBox* aBox, nsBoxLayoutState& aState,
+                              nsIBox* aPrevBox, nsIBox* aChildList);
+  NS_IMETHOD ChildrenAppended(nsIBox* aBox, nsBoxLayoutState& aState,
+                              nsIBox* aChildList);
+  NS_IMETHOD ChildrenRemoved(nsIBox* aBox, nsBoxLayoutState& aState,
+                             nsIBox* aChildList);
+  NS_IMETHOD ChildrenSet(nsIBox* aBox, nsBoxLayoutState& aState,
+                         nsIBox* aChildList);
 protected:
 
   nsGridLayout2(nsIPresShell* aShell);