2 files changed, 16 insertions, 0 deletions
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index 5dfbb8dba6..d4fbebbf2f 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -8192,6 +8192,9 @@ PresShell::HandleEventInternal(WidgetEvent* aEvent,
           }
         }
       }
+      if (aEvent->mMessage == eKeyDown) {
+        mIsLastKeyDownCanceled = aEvent->mFlags.mDefaultPrevented;
+      }
       break;
     }
     case eMouseUp:
@@ -8981,6 +8984,9 @@ PresShell::FireOrClearDelayedEvents(bool aFireEvents)
            !doc->EventHandlingSuppressed()) {
       nsAutoPtr<DelayedEvent> ev(mDelayedEvents[0].forget());
       mDelayedEvents.RemoveElementAt(0);
+      if (ev->IsKeyPressEvent() && mIsLastKeyDownCanceled) {
+        continue;
+      }
       ev->Dispatch();
     }
     if (!doc->EventHandlingSuppressed()) {
@@ -9775,6 +9781,12 @@ PresShell::DelayedKeyEvent::DelayedKeyEvent(WidgetKeyboardEvent* aEvent) :
   mEvent = keyEvent;
 }
 
+bool
+PresShell::DelayedKeyEvent::IsKeyPressEvent()
+{
+  return mEvent->mMessage == eKeyPress;
+}
+
 // Start of DEBUG only code
 
 #ifdef DEBUG
diff --git a/layout/base/nsPresShell.h b/layout/base/nsPresShell.h
index 7a9056a383..1a8dd3fefa 100644
--- a/layout/base/nsPresShell.h
+++ b/layout/base/nsPresShell.h
@@ -617,6 +617,7 @@ protected:
   public:
     virtual ~DelayedEvent() { }
     virtual void Dispatch() { }
+    virtual bool IsKeyPressEvent() { return false; }
   };
 
   class DelayedInputEvent : public DelayedEvent
@@ -641,6 +642,7 @@ protected:
   {
   public:
     explicit DelayedKeyEvent(mozilla::WidgetKeyboardEvent* aEvent);
+    virtual bool IsKeyPressEvent() override;
   };
 
   // Check if aEvent is a mouse event and record the mouse location for later
@@ -951,6 +953,8 @@ protected:
   // Whether the widget has received a paint message yet.
   bool                      mHasReceivedPaintMessage : 1;
 
+  bool                      mIsLastKeyDownCanceled : 1;
+
   static bool               sDisableNonTestMouseEvents;
 };