--- a/widget/PuppetWidget.cpp
+++ b/widget/PuppetWidget.cpp
@@ -1430,16 +1430,17 @@ PuppetWidget::HasPendingInputEvent()
           case mozilla::dom::PBrowser::Msg_RealKeyEvent__ID:
           case mozilla::dom::PBrowser::Msg_MouseWheelEvent__ID:
           case mozilla::dom::PBrowser::Msg_RealTouchEvent__ID:
           case mozilla::dom::PBrowser::Msg_RealTouchMoveEvent__ID:
           case mozilla::dom::PBrowser::Msg_RealDragEvent__ID:
           case mozilla::dom::PBrowser::Msg_UpdateDimensions__ID:
           case mozilla::dom::PBrowser::Msg_MouseEvent__ID:
           case mozilla::dom::PBrowser::Msg_KeyEvent__ID:
+          case mozilla::dom::PBrowser::Msg_SetDocShellIsActive__ID:
             ret = true;
             return false;  // Stop peeking.
         }
       }
       return true;
     }
   );