Bug 293453. Hack scrolled frame NS_FRAME_OUTSIDE_CHILDREN to work around event handling bug. r+sr=bzbarsky,a=asa

layout/generic/nsGfxScrollFrame.cpp

@@ -631,6 +631,9 @@ nsHTMLScrollFrame::PlaceScrollArea(const ScrollReflowState& aState)
                             PR_MAX(childOverflow.XMost(), aState.mScrollPortRect.width),
                             PR_MAX(childOverflow.YMost(), aState.mScrollPortRect.height));
   mInner.mScrolledFrame->SetRect(childRect);
+  // XXX hack! force the scrolled frame to think it has overflow
+  // to avoid problems with incorrect event targeting.
+  mInner.mScrolledFrame->AddStateBits(NS_FRAME_OUTSIDE_CHILDREN);
 
   nsContainerFrame::SyncFrameViewAfterReflow(mInner.mScrolledFrame->GetPresContext(),
                                              mInner.mScrolledFrame,
@@ -2000,6 +2003,9 @@ nsXULScrollFrame::LayoutScrollArea(nsBoxLayoutState& aState, const nsRect& aRect
   aState.SetLayoutFlags(oldflags);
 
   childRect = mInner.mScrolledFrame->GetRect();
+  // XXX hack! force the scrolled frame to think it has overflow
+  // to avoid problems with incorrect event targeting.
+  mInner.mScrolledFrame->AddStateBits(NS_FRAME_OUTSIDE_CHILDREN);
 
   // first see what changed
   PRBool vertChanged = PR_FALSE;