--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -67,16 +67,17 @@
 #include "FrameLayerBuilder.h"
 #include "mozilla/EventStateManager.h"
 #include "RestyleManager.h"
 #include "nsCaret.h"
 #include "nsISelection.h"
 #include "nsDOMTokenList.h"
 #include "mozilla/RuleNodeCacheConditions.h"
 #include "nsCSSProps.h"
+#include "nsPluginFrame.h"
 
 // GetCurrentTime is defined in winbase.h as zero argument macro forwarding to
 // GetTickCount().
 #ifdef GetCurrentTime
 #undef GetCurrentTime
 #endif
 
 using namespace mozilla;
@@ -3210,16 +3211,23 @@ nsDisplayLayerEventRegions::AddFrame(nsD
   if (borderBoxHasRoundedCorners ||
       (aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT)) {
     mMaybeHitRegion.Or(mMaybeHitRegion, borderBox);
   } else {
     mHitRegion.Or(mHitRegion, borderBox);
   }
   if (aBuilder->GetAncestorHasApzAwareEventHandler()) {
     mDispatchToContentHitRegion.Or(mDispatchToContentHitRegion, borderBox);
+  } else if (aFrame->GetType() == nsGkAtoms::objectFrame) {
+    // If the frame is a plugin frame and wants to handle wheel events as
+    // default action, we should add the frame to dispatch-to-content region.
+    nsPluginFrame* pluginFrame = do_QueryFrame(aFrame);
+    if (pluginFrame && pluginFrame->WantsToHandleWheelEventAsDefaultAction()) {
+      mDispatchToContentHitRegion.Or(mDispatchToContentHitRegion, borderBox);
+    }
   }
 
   // Touch action region
 
   uint32_t touchAction = nsLayoutUtils::GetTouchActionFromFrame(aFrame);
   if (touchAction & NS_STYLE_TOUCH_ACTION_NONE) {
     mNoActionRegion.Or(mNoActionRegion, borderBox);
   } else {