--- a/layout/base/FrameLayerBuilder.cpp
+++ b/layout/base/FrameLayerBuilder.cpp
@@ -3269,16 +3269,17 @@ void ContainerState::FinishPaintedLayerD
     }
     if (!data->mMaybeHitRegion.GetBounds().IsEmpty()) {
       nsRect rect = nsLayoutUtils::TransformFrameRectToAncestor(
         mContainerReferenceFrame,
         data->mMaybeHitRegion.GetBounds(),
         containingPaintedLayerData->mReferenceFrame);
       containingPaintedLayerData->mMaybeHitRegion.Or(
         containingPaintedLayerData->mMaybeHitRegion, rect);
+      containingPaintedLayerData->mMaybeHitRegion.SimplifyOutward(8);
     }
     nsLayoutUtils::TransformToAncestorAndCombineRegions(
       data->mHitRegion.GetBounds(),
       mContainerReferenceFrame,
       containingPaintedLayerData->mReferenceFrame,
       &containingPaintedLayerData->mHitRegion,
       &containingPaintedLayerData->mMaybeHitRegion);
     nsLayoutUtils::TransformToAncestorAndCombineRegions(