--- a/gfx/layers/apz/src/APZCTreeManager.cpp
+++ b/gfx/layers/apz/src/APZCTreeManager.cpp
@@ -397,29 +397,16 @@ APZCTreeManager::PrepareAPZCForLayer(con
       apzc->AddHitTestRegions(EventRegions(unobscured));
       APZCTM_LOG("Adding region %s to visible region of APZC %p\n", Stringify(unobscured).c_str(), apzc);
     }
   }
 
   return apzc;
 }
 
-static EventRegions
-EventRegionsFor(const LayerMetricsWrapper& aLayer)
-{
-  // This is a workaround for bug 1082594. We should be able to replace this
-  // with just a call to aLayer.GetEventRegions() once that bug is fixed.
-  if (aLayer.IsScrollInfoLayer()) {
-    EventRegions regions(ParentLayerIntRect::ToUntyped(RoundedIn(aLayer.Metrics().mCompositionBounds)));
-    regions.mDispatchToContentHitRegion = regions.mHitRegion;
-    return regions;
-  }
-  return aLayer.GetEventRegions();
-}
-
 AsyncPanZoomController*
 APZCTreeManager::UpdatePanZoomControllerTree(TreeBuildingState& aState,
                                              const LayerMetricsWrapper& aLayer,
                                              uint64_t aLayersId,
                                              const gfx::Matrix4x4& aAncestorTransform,
                                              AsyncPanZoomController* aParent,
                                              AsyncPanZoomController* aNextSibling,
                                              const nsIntRegion& aObscured)
@@ -492,17 +479,17 @@ APZCTreeManager::UpdatePanZoomController
     next = UpdatePanZoomControllerTree(aState, child, childLayersId,
                                        ancestorTransform, aParent, next,
                                        obscured);
 
     // Each layer obscures its previous siblings, so we augment the obscured
     // region as we loop backwards through the children.
     nsIntRegion childRegion;
     if (gfxPrefs::LayoutEventRegionsEnabled()) {
-      childRegion = EventRegionsFor(child).mHitRegion;
+      childRegion = child.GetEventRegions().mHitRegion;
     } else {
       childRegion = child.GetVisibleRegion();
     }
     childRegion.Transform(gfx::To3DMatrix(child.GetTransform()));
     if (child.GetClipRect()) {
       childRegion.AndWith(*child.GetClipRect());
     }
 
@@ -526,17 +513,17 @@ APZCTreeManager::UpdatePanZoomController
     // When we compute the unobscured regions below, we subtract off the
     // |obscured| region, but it would also be ok to do this before the above
     // loop. At that point |obscured| would only have the uncles' hit regions
     // and not the children. The reason this is ok is again because of the way
     // we do hit-testing (where the deepest APZC is used) it doesn't matter if
     // we count the children as obscuring the parent or not.
 
     EventRegions unobscured;
-    unobscured.Sub(EventRegionsFor(aLayer), obscured);
+    unobscured.Sub(aLayer.GetEventRegions(), obscured);
     APZCTM_LOG("Picking up unobscured hit region %s from layer %p\n", Stringify(unobscured).c_str(), aLayer.GetLayer());
 
     // Take the hit region of the |aLayer|'s subtree (which has already been
     // transformed into the coordinate space of |aLayer|) and...
     EventRegions subtreeEventRegions = aState.mEventRegions.LastElement();
     aState.mEventRegions.RemoveElementAt(aState.mEventRegions.Length() - 1);
     // ... combine it with the hit region for this layer, and then ...
     subtreeEventRegions.OrWith(unobscured);

--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -2885,16 +2885,22 @@ nsDisplayLayerEventRegions::AddFrame(nsD
   } else {
     mHitRegion.Or(mHitRegion, borderBox);
   }
   if (aBuilder->GetAncestorHasTouchEventHandler()) {
     mDispatchToContentHitRegion.Or(mDispatchToContentHitRegion, borderBox);
   }
 }
 
+void
+nsDisplayLayerEventRegions::AddInactiveScrollPort(const nsRect& aRect)
+{
+  mDispatchToContentHitRegion.Or(mDispatchToContentHitRegion, aRect);
+}
+
 nsDisplayCaret::nsDisplayCaret(nsDisplayListBuilder* aBuilder,
                                nsIFrame* aCaretFrame)
   : nsDisplayItem(aBuilder, aCaretFrame)
   , mCaret(aBuilder->GetCaret())
   , mBounds(aBuilder->GetCaretRect() + ToReferenceFrame())
 {
   MOZ_COUNT_CTOR(nsDisplayCaret);
 }

--- a/layout/base/nsDisplayList.h
+++ b/layout/base/nsDisplayList.h
@@ -2578,16 +2578,21 @@ public:
   }
 
   NS_DISPLAY_DECL_NAME("LayerEventRegions", TYPE_LAYER_EVENT_REGIONS)
 
   // Indicate that aFrame's border-box contributes to the event regions for
   // this layer. aFrame must have the same reference frame as mFrame.
   void AddFrame(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame);
 
+  // Indicate that an inactive scrollframe's scrollport should be added to the
+  // dispatch-to-content region, to ensure that APZ lets content create a
+  // displayport.
+  void AddInactiveScrollPort(const nsRect& aRect);
+
   const nsRegion& HitRegion() { return mHitRegion; }
   const nsRegion& MaybeHitRegion() { return mMaybeHitRegion; }
   const nsRegion& DispatchToContentHitRegion() { return mDispatchToContentHitRegion; }
 
 private:
   // Relative to aFrame's reference frame.
   // These are the points that are definitely in the hit region.
   nsRegion mHitRegion;

--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -2947,16 +2947,27 @@ ScrollFrameHelper::BuildDisplayList(nsDi
       nsLayoutUtils::WantSubAPZC() &&
       WantAsyncScroll() &&
       // If we are the root scroll frame for the display root then we don't need a scroll
       // info layer to make a ComputeFrameMetrics call for us as
       // nsDisplayList::PaintForFrame already calls ComputeFrameMetrics for us.
       (!mIsRoot || aBuilder->RootReferenceFrame()->PresContext() != mOuter->PresContext());
   }
 
+  if (aBuilder->IsPaintingToWindow() &&
+      !mShouldBuildScrollableLayer &&
+      shouldBuildLayer)
+  {
+    if (nsDisplayLayerEventRegions *eventRegions = aBuilder->GetLayerEventRegions()) {
+      // Make sure that APZ will dispatch events back to content so we can
+      // create a displayport for this frame.
+      eventRegions->AddInactiveScrollPort(mScrollPort + aBuilder->ToReferenceFrame(mOuter));
+    }
+  }
+
   mScrollParentID = aBuilder->GetCurrentScrollParentId();
 
   nsDisplayListCollection scrolledContent;
   {
     // Note that setting the current scroll parent id here means that positioned children
     // of this scroll info layer will pick up the scroll info layer as their scroll handoff
     // parent. This is intentional because that is what happens for positioned children
     // of scroll layers, and we want to maintain consistent behaviour between scroll layers