--- a/layout/xul/nsSliderFrame.cpp
+++ b/layout/xul/nsSliderFrame.cpp
@@ -925,18 +925,22 @@ nsSliderMediator::HandleEvent(nsIDOMEven
   // Only process the event if the thumb is not being dragged.
   if (mSlider && !mSlider->isDraggingThumb())
     return mSlider->StartDrag(aEvent);
 
   return NS_OK;
 }
 
 bool
-nsSliderFrame::StartAPZDrag()
+nsSliderFrame::StartAPZDrag(WidgetGUIEvent* aEvent)
 {
+  if (!aEvent->mFlags.mHandledByAPZ) {
+    return false;
+  }
+
   if (!gfxPlatform::GetPlatform()->SupportsApzDragInput()) {
     return false;
   }
 
   nsContainerFrame* scrollFrame = GetScrollbar()->GetParent();
   if (!scrollFrame) {
     return false;
   }
@@ -1051,17 +1055,17 @@ nsSliderFrame::StartDrag(nsIDOMEvent* aE
 
   if (isHorizontal)
     mThumbStart = thumbFrame->GetPosition().x;
   else
     mThumbStart = thumbFrame->GetPosition().y;
 
   mDragStart = pos - mThumbStart;
 
-  mScrollingWithAPZ = StartAPZDrag();
+  mScrollingWithAPZ = StartAPZDrag(event);
 
 #ifdef DEBUG_SLIDER
   printf("Pressed mDragStart=%d\n",mDragStart);
 #endif
 
   if (!mScrollingWithAPZ && !mSuppressionActive) {
     MOZ_ASSERT(PresContext()->PresShell());
     APZCCallbackHelper::SuppressDisplayport(true, PresContext()->PresShell());

--- a/layout/xul/nsSliderFrame.h
+++ b/layout/xul/nsSliderFrame.h
@@ -95,17 +95,17 @@ public:
                             nsIFrame*       aPrevFrame,
                             nsFrameList&    aFrameList) override;
   virtual void RemoveFrame(ChildListID     aListID,
                            nsIFrame*       aOldFrame) override;
 
   nsresult StartDrag(nsIDOMEvent* aEvent);
   nsresult StopDrag();
 
-  bool StartAPZDrag();
+  bool StartAPZDrag(WidgetGUIEvent* aEvent);
 
   static int32_t GetCurrentPosition(nsIContent* content);
   static int32_t GetMinPosition(nsIContent* content);
   static int32_t GetMaxPosition(nsIContent* content);
   static int32_t GetIncrement(nsIContent* content);
   static int32_t GetPageIncrement(nsIContent* content);
   static int32_t GetIntegerAttribute(nsIContent* content, nsIAtom* atom, int32_t defaultValue);
   void EnsureOrient();