--- a/b2g/chrome/content/content.css
+++ b/b2g/chrome/content/content.css
@@ -25,29 +25,24 @@ html xul|scrollbar[root="true"] {
 html xul|scrollbar {
   -moz-appearance: none !important;
   background-color: transparent !important;
   background-image: none !important;
   border: 0px solid transparent !important;
   pointer-events: none;
 }
 
+/* Scrollbar code will reset the margin to the correct side depending on
+   where layout actually puts the scrollbar */
 xul|scrollbar[orient="vertical"] {
-  -moz-margin-start: -8px;
+  margin-left: -8px;
   min-width: 8px;
   max-width: 8px;
 }
 
-/* workaround for bug 1119057: as -moz-margin-start may not work as expected,
- * force a right margin value in RTL mode.  */
-[dir="rtl"] xul|scrollbar[root="true"][orient="vertical"] {
-  -moz-margin-start: unset;
-  margin-right: -8px;
-}
-
 xul|scrollbar[orient="vertical"] xul|thumb {
   max-width: 6px !important;
   min-width: 6px !important;
 }
 
 xul|scrollbar[orient="horizontal"] {
   margin-top: -8px;
   min-height: 8px;

--- a/browser/themes/linux/devtools/floating-scrollbars.css
+++ b/browser/themes/linux/devtools/floating-scrollbars.css
@@ -4,18 +4,20 @@ scrollbar {
   -moz-appearance: none !important;
   position: relative;
   background-color: transparent;
   background-image: none;
   z-index: 2147483647;
   padding: 2px;
 }
 
+/* Scrollbar code will reset the margin to the correct side depending on
+   where layout actually puts the scrollbar */
 scrollbar[orient="vertical"] {
-  -moz-margin-start: -10px;
+  margin-left: -10px;
   min-width: 10px;
   max-width: 10px;
 }
 
 scrollbar[orient="horizontal"] {
   margin-top: -10px;
   min-height: 10px;
   max-height: 10px;

--- a/browser/themes/osx/devtools/floating-scrollbars.css
+++ b/browser/themes/osx/devtools/floating-scrollbars.css
@@ -5,18 +5,20 @@ scrollbar {
   position: relative;
   background-color: transparent;
   background-image: none;
   border: 0px solid transparent;
   z-index: 2147483647;
   padding: 2px;
 }
 
+/* Scrollbar code will reset the margin to the correct side depending on
+   where layout actually puts the scrollbar */
 scrollbar[orient="vertical"] {
-  -moz-margin-start: -8px;
+  margin-left: -8px;
   min-width: 8px;
   max-width: 8px;
 }
 
 scrollbar[orient="horizontal"] {
   margin-top: -8px;
   min-height: 8px;
   max-height: 8px;

--- a/browser/themes/windows/devtools/floating-scrollbars.css
+++ b/browser/themes/windows/devtools/floating-scrollbars.css
@@ -4,18 +4,20 @@ scrollbar {
   -moz-appearance: none !important;
   position: relative;
   background-color: transparent;
   background-image: none;
   z-index: 2147483647;
   padding: 2px;
 }
 
+/* Scrollbar code will reset the margin to the correct side depending on
+   where layout actually puts the scrollbar */
 scrollbar[orient="vertical"] {
-  -moz-margin-start: -10px;
+  margin-left: -10px;
   min-width: 10px;
   max-width: 10px;
 }
 
 scrollbar[orient="horizontal"] {
   margin-top: -10px;
   min-height: 10px;
   max-height: 10px;

--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -396,17 +396,17 @@ nsHTMLScrollFrame::TryLayout(ScrollReflo
   }
 
   nscoord vScrollbarActualWidth = aState->mInsideBorderSize.width - scrollPortSize.width;
 
   aState->mShowHScrollbar = aAssumeHScroll;
   aState->mShowVScrollbar = aAssumeVScroll;
   nsPoint scrollPortOrigin(aState->mComputedBorder.left,
                            aState->mComputedBorder.top);
-  if (!mHelper.IsScrollbarOnRight()) {
+  if (!IsScrollbarOnRight()) {
     scrollPortOrigin.x += vScrollbarActualWidth;
   }
   mHelper.mScrollPort = nsRect(scrollPortOrigin, scrollPortSize);
   return true;
 }
 
 bool
 nsHTMLScrollFrame::ScrolledContentDependsOnHeight(ScrollReflowState* aState)
@@ -4270,17 +4270,17 @@ ScrollFrameHelper::IsScrollingActive(nsD
 
 /**
  * Reflow the scroll area if it needs it and return its size. Also determine if the reflow will
  * cause any of the scrollbars to need to be reflowed.
  */
 nsresult
 nsXULScrollFrame::Layout(nsBoxLayoutState& aState)
 {
-  bool scrollbarRight = mHelper.IsScrollbarOnRight();
+  bool scrollbarRight = IsScrollbarOnRight();
   bool scrollbarBottom = true;
 
   // get the content rect
   nsRect clientRect(0,0,0,0);
   GetClientRect(clientRect);
 
   nsRect oldScrollAreaBounds = mHelper.mScrollPort;
   nsPoint oldScrollPosition = mHelper.GetLogicalScrollPosition();

--- a/layout/generic/nsGfxScrollFrame.h
+++ b/layout/generic/nsGfxScrollFrame.h
@@ -893,16 +893,20 @@ public:
   }
   virtual void VisibilityChanged(bool aVisible) override {}
   virtual nsIFrame* GetScrollbarBox(bool aVertical) override {
     return mHelper.GetScrollbarBox(aVertical);
   }
   virtual void ScrollbarActivityStarted() const override;
   virtual void ScrollbarActivityStopped() const override;
 
+  virtual bool IsScrollbarOnRight() const override {
+    return mHelper.IsScrollbarOnRight();
+  }
+
   virtual void SetTransformingByAPZ(bool aTransforming) override {
     mHelper.SetTransformingByAPZ(aTransforming);
   }
   bool IsTransformingByAPZ() const override {
     return mHelper.IsTransformingByAPZ();
   }
   
 #ifdef DEBUG_FRAME_DUMP
@@ -1290,16 +1294,20 @@ public:
   virtual void VisibilityChanged(bool aVisible) override {}
   virtual nsIFrame* GetScrollbarBox(bool aVertical) override {
     return mHelper.GetScrollbarBox(aVertical);
   }
 
   virtual void ScrollbarActivityStarted() const override;
   virtual void ScrollbarActivityStopped() const override;
 
+  virtual bool IsScrollbarOnRight() const override {
+    return mHelper.IsScrollbarOnRight();
+  }
+
   virtual void SetTransformingByAPZ(bool aTransforming) override {
     mHelper.SetTransformingByAPZ(aTransforming);
   }
   bool IsTransformingByAPZ() const override {
     return mHelper.IsTransformingByAPZ();
   }
 
 #ifdef DEBUG_FRAME_DUMP

--- a/layout/xul/nsIScrollbarMediator.h
+++ b/layout/xul/nsIScrollbarMediator.h
@@ -72,12 +72,14 @@ public:
    */
   virtual nsIFrame* GetScrollbarBox(bool aVertical) = 0;
   /**
    * Show or hide scrollbars on 2 fingers touch.
    * Subclasses should call their ScrollbarActivity's corresponding methods.
    */
   virtual void ScrollbarActivityStarted() const = 0;
   virtual void ScrollbarActivityStopped() const = 0;
+
+  virtual bool IsScrollbarOnRight() const = 0;
 };
 
 #endif
 

--- a/layout/xul/nsListBoxBodyFrame.h
+++ b/layout/xul/nsListBoxBodyFrame.h
@@ -67,16 +67,19 @@ public:
   virtual void ThumbMoved(nsScrollbarFrame* aScrollbar,
                           int32_t aOldPos,
                           int32_t aNewPos) override;
   virtual void ScrollbarReleased(nsScrollbarFrame* aScrollbar) override {}
   virtual void VisibilityChanged(bool aVisible) override;
   virtual nsIFrame* GetScrollbarBox(bool aVertical) override;
   virtual void ScrollbarActivityStarted() const override {}
   virtual void ScrollbarActivityStopped() const override {}
+  virtual bool IsScrollbarOnRight() const override {
+    return (StyleVisibility()->mDirection == NS_STYLE_DIRECTION_LTR);
+  }
 
 
   // nsIReflowCallback
   virtual bool ReflowFinished() override;
   virtual void ReflowCallbackCanceled() override;
 
   NS_IMETHOD DoLayout(nsBoxLayoutState& aBoxLayoutState) override;
   virtual void MarkIntrinsicISizesDirty() override;

--- a/layout/xul/nsScrollbarFrame.cpp
+++ b/layout/xul/nsScrollbarFrame.cpp
@@ -164,42 +164,49 @@ nsScrollbarFrame::GetScrollbarMediator()
     }
   }
   return sbm;
 }
 
 nsresult
 nsScrollbarFrame::GetMargin(nsMargin& aMargin)
 {
+  nsresult rv = NS_ERROR_FAILURE;
   aMargin.SizeTo(0,0,0,0);
 
   if (LookAndFeel::GetInt(LookAndFeel::eIntID_UseOverlayScrollbars) != 0) {
     nsPresContext* presContext = PresContext();
     nsITheme* theme = presContext->GetTheme();
     if (theme) {
       LayoutDeviceIntSize size;
       bool isOverridable;
       theme->GetMinimumWidgetSize(presContext, this, NS_THEME_SCROLLBAR, &size,
                                   &isOverridable);
       if (IsHorizontal()) {
         aMargin.top = -presContext->DevPixelsToAppUnits(size.height);
       }
       else {
-        if (StyleVisibility()->mDirection == NS_STYLE_DIRECTION_RTL) {
-          aMargin.right = -presContext->DevPixelsToAppUnits(size.width);
-        }
-        else {
-          aMargin.left = -presContext->DevPixelsToAppUnits(size.width);
-        }
+        aMargin.left = -presContext->DevPixelsToAppUnits(size.width);
       }
-      return NS_OK;
+      rv = NS_OK;
     }
   }
 
-  return nsBox::GetMargin(aMargin);
+  if (NS_FAILED(rv)) {
+    rv = nsBox::GetMargin(aMargin);
+  }
+
+  if (NS_SUCCEEDED(rv) && !IsHorizontal()) {
+    nsIScrollbarMediator* scrollFrame = GetScrollbarMediator();
+    if (scrollFrame && !scrollFrame->IsScrollbarOnRight()) {
+      Swap(aMargin.left, aMargin.right);
+    }
+  }
+
+  return rv;
 }
 
 void
 nsScrollbarFrame::SetIncrementToLine(int32_t aDirection)
 {
   // get the scrollbar's content node
   nsIContent* content = GetContent();
   mSmoothScroll = true;

--- a/layout/xul/tree/nsTreeBodyFrame.h
+++ b/layout/xul/tree/nsTreeBodyFrame.h
@@ -149,16 +149,19 @@ public:
   virtual void ScrollbarReleased(nsScrollbarFrame* aScrollbar) override {}
   virtual void VisibilityChanged(bool aVisible) override { Invalidate(); }
   virtual nsIFrame* GetScrollbarBox(bool aVertical) override {
     ScrollParts parts = GetScrollParts();
     return aVertical ? parts.mVScrollbar : parts.mHScrollbar;
   }
   virtual void ScrollbarActivityStarted() const override;
   virtual void ScrollbarActivityStopped() const override;
+  virtual bool IsScrollbarOnRight() const override {
+    return (StyleVisibility()->mDirection == NS_STYLE_DIRECTION_LTR);
+  }
 
   // Overridden from nsIFrame to cache our pres context.
   virtual void Init(nsIContent*       aContent,
                     nsContainerFrame* aParent,
                     nsIFrame*         aPrevInFlow) override;
   virtual void DestroyFrom(nsIFrame* aDestructRoot) override;
 
   virtual nsresult GetCursor(const nsPoint& aPoint,

--- a/mobile/android/themes/core/content.css
+++ b/mobile/android/themes/core/content.css
@@ -28,21 +28,16 @@ xul|window xul|scrollbar[orient="vertica
   position: relative;
   margin-left: -8px;
   min-width: 8px;
   background-color: transparent !important;
   background-image: none !important;
   border: 0px solid transparent !important;
 }
 
-xul|window xul|scrollbar[orient="vertical"]:-moz-locale-dir(rtl) {
-  margin-left: 2px;
-  margin-right: -10px;
-}
-
 xul|window xul|scrollbar[orient="vertical"] xul|thumb {
   max-width: 6px !important;
   min-width: 6px !important;
 }
 
 xul|window xul|scrollbar[orient="horizontal"] {
   -moz-appearance: none !important;
   opacity: 0;