--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -1098,16 +1098,17 @@ GK_ATOM(range, "range")
 GK_ATOM(readonly, "readonly")
 GK_ATOM(rect, "rect")
 GK_ATOM(rectangle, "rectangle")
 GK_ATOM(ref, "ref")
 GK_ATOM(refresh, "refresh")
 GK_ATOM(rel, "rel")
 GK_ATOM(onreloadpage, "onreloadpage")
 GK_ATOM(rem, "rem")
+GK_ATOM(remote, "remote")
 GK_ATOM(removeelement, "removeelement")
 GK_ATOM(renderingobserverlist, "renderingobserverlist")
 GK_ATOM(repeat, "repeat")
 GK_ATOM(replace, "replace")
 GK_ATOM(required, "required")
 GK_ATOM(reserved, "reserved")
 GK_ATOM(reset, "reset")
 GK_ATOM(resizeafter, "resizeafter")

--- a/layout/xul/nsMenuPopupFrame.cpp
+++ b/layout/xul/nsMenuPopupFrame.cpp
@@ -185,16 +185,24 @@ nsMenuPopupFrame::Init(nsIContent*      
       rootBox->SetDefaultTooltip(aContent);
     }
   }
 
   AddStateBits(NS_FRAME_IN_POPUP);
 }
 
 bool
+nsMenuPopupFrame::HasRemoteContent() const
+{
+  return (!mInContentShell && mPopupType == ePopupTypePanel &&
+          mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::remote,
+                                nsGkAtoms::_true, eIgnoreCase));
+}
+
+bool
 nsMenuPopupFrame::IsNoAutoHide() const
 {
   // Panels with noautohide="true" don't hide when the mouse is clicked
   // outside of them, or when another application is made active. Non-autohide
   // panels cannot be used in content windows.
   return (!mInContentShell && mPopupType == ePopupTypePanel &&
            mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::noautohide,
                                  nsGkAtoms::_true, eIgnoreCase));
@@ -235,19 +243,22 @@ nsMenuPopupFrame::PopupLevel(bool aIsNoA
   if (aIsNoAutoHide)
     return ePopupLevelParent;
 
   // Otherwise, the result depends on the platform.
   return sDefaultLevelIsTop ? ePopupLevelTop : ePopupLevelParent;
 }
 
 void
-nsMenuPopupFrame::EnsureWidget()
+nsMenuPopupFrame::EnsureWidget(bool aRecreate)
 {
   nsView* ourView = GetView();
+  if (aRecreate) {
+    ourView->DestroyWidget();
+  }
   if (!ourView->HasWidget()) {
     NS_ASSERTION(!mGeneratedChildren && !PrincipalChildList().FirstChild(),
                  "Creating widget for MenuPopupFrame with children");
     CreateWidgetForView(ourView);
   }
 }
 
 nsresult
@@ -286,21 +297,24 @@ nsMenuPopupFrame::CreateWidgetForView(ns
       if (mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::close,
                                 nsGkAtoms::_true, eCaseMatters)) {
         widgetData.mBorderStyle =
           static_cast<enum nsBorderStyle>(widgetData.mBorderStyle | eBorderStyle_close);
       }
     }
   }
 
+  bool remote = HasRemoteContent();
+
   nsTransparencyMode mode = nsLayoutUtils::GetFrameTransparency(this, this);
   nsIContent* parentContent = GetContent()->GetParent();
   nsIAtom *tag = nullptr;
   if (parentContent && parentContent->IsXULElement())
     tag = parentContent->NodeInfo()->NameAtom();
+  widgetData.mHasRemoteContent = remote;
   widgetData.mSupportTranslucency = mode == eTransparencyTransparent;
   widgetData.mDropShadow = !(mode == eTransparencyTransparent || tag == nsGkAtoms::menulist);
   widgetData.mPopupLevel = PopupLevel(widgetData.mNoAutoHide);
 
   // panels which have a parent level need a parent widget. This allows them to
   // always appear in front of the parent window but behind other windows that
   // should be in front of it.
   nsCOMPtr<nsIWidget> parentWidget;
@@ -2229,16 +2243,23 @@ nsMenuPopupFrame::AttributeChanged(int32
 #ifndef MOZ_GTK2
   if (aAttribute == nsGkAtoms::noautohide) {
     nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
     if (pm)
       pm->EnableRollup(mContent, !IsNoAutoHide());
   }
 #endif
 
+  if (aAttribute == nsGkAtoms::remote) {
+    // When the remote attribute changes, we need to create a new widget to
+    // ensure that it has the correct compositor and transparency settings to
+    // match the new value.
+    EnsureWidget(true);
+  }
+
   if (aAttribute == nsGkAtoms::followanchor) {
     nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
     if (pm) {
       pm->UpdateFollowAnchor(this);
     }
   }
 
   if (aAttribute == nsGkAtoms::label) {

--- a/layout/xul/nsMenuPopupFrame.h
+++ b/layout/xul/nsMenuPopupFrame.h
@@ -220,26 +220,31 @@ public:
                     nsIFrame*         aPrevInFlow) override;
 
   virtual nsresult AttributeChanged(int32_t aNameSpaceID,
                                     nsIAtom* aAttribute,
                                     int32_t aModType) override;
 
   virtual void DestroyFrom(nsIFrame* aDestructRoot) override;
 
+  bool HasRemoteContent() const;
+
   // returns true if the popup is a panel with the noautohide attribute set to
   // true. These panels do not roll up automatically.
   bool IsNoAutoHide() const;
 
   nsPopupLevel PopupLevel() const
   {
     return PopupLevel(IsNoAutoHide()); 
   }
 
-  void EnsureWidget();
+  // Ensure that a widget has already been created for this view, and create
+  // one if it hasn't. If aRecreate is true, destroys any existing widget and
+  // creates a new one, regardless of whether one has already been created.
+  void EnsureWidget(bool aRecreate = false);
 
   nsresult CreateWidgetForView(nsView* aView);
   uint8_t GetShadowStyle();
 
   virtual void SetInitialChildList(ChildListID  aListID,
                                    nsFrameList& aChildList) override;
 
   virtual bool IsLeaf() const override;

--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -158,16 +158,17 @@ nsBaseWidget::nsBaseWidget()
 , mCursor(eCursor_standard)
 , mBorderStyle(eBorderStyle_none)
 , mBounds(0,0,0,0)
 , mOriginalBounds(nullptr)
 , mClipRectCount(0)
 , mSizeMode(nsSizeMode_Normal)
 , mPopupLevel(ePopupLevelTop)
 , mPopupType(ePopupTypeAny)
+, mHasRemoteContent(false)
 , mCompositorWidgetDelegate(nullptr)
 , mUpdateCursor(true)
 , mUseAttachedEvents(false)
 , mIMEHasFocus(false)
 #if defined(XP_WIN) || defined(XP_MACOSX) || defined(MOZ_WIDGET_GTK)
 , mAccessibilityInUseFlag(false)
 #endif
 {
@@ -375,16 +376,17 @@ void nsBaseWidget::BaseCreate(nsIWidget*
   }
 
   // keep a reference to the device context
   if (nullptr != aInitData) {
     mWindowType = aInitData->mWindowType;
     mBorderStyle = aInitData->mBorderStyle;
     mPopupLevel = aInitData->mPopupLevel;
     mPopupType = aInitData->mPopupHint;
+    mHasRemoteContent = aInitData->mHasRemoteContent;
   }
 
   if (aParent) {
     aParent->AddChild(this);
   }
 }
 
 //-------------------------------------------------------------------------

--- a/widget/nsBaseWidget.h
+++ b/widget/nsBaseWidget.h
@@ -544,16 +544,18 @@ protected:
     nsCOMPtr<nsIWidget> widget = do_CreateInstance(kCPopUpCID);
     return widget.forget();
   }
 
   LayerManager* CreateBasicLayerManager();
 
   nsPopupType PopupType() const { return mPopupType; }
 
+  bool HasRemoteContent() const { return mHasRemoteContent; }
+
   void NotifyRollupGeometryChange()
   {
     // XULPopupManager isn't interested in this notification, so only
     // send it if gRollupListener is set.
     if (gRollupListener) {
       gRollupListener->NotifyGeometryChange();
     }
   }
@@ -678,16 +680,17 @@ protected:
   LayoutDeviceIntRect* mOriginalBounds;
   // When this pointer is null, the widget is not clipped
   mozilla::UniquePtr<LayoutDeviceIntRect[]> mClipRects;
   uint32_t          mClipRectCount;
   nsSizeMode        mSizeMode;
   nsPopupLevel      mPopupLevel;
   nsPopupType       mPopupType;
   SizeConstraints   mSizeConstraints;
+  bool              mHasRemoteContent;
 
   CompositorWidgetDelegate* mCompositorWidgetDelegate;
 
   bool              mUpdateCursor;
   bool              mUseAttachedEvents;
   bool              mIMEHasFocus;
 #if defined(XP_WIN) || defined(XP_MACOSX) || defined(MOZ_WIDGET_GTK)
   bool              mAccessibilityInUseFlag;

--- a/widget/nsWidgetInitData.h
+++ b/widget/nsWidgetInitData.h
@@ -100,17 +100,18 @@ struct nsWidgetInitData {
       mDropShadow(false),
       mListenForResizes(false),
       mUnicode(true),
       mRTL(false),
       mNoAutoHide(false),
       mIsDragPopup(false),
       mIsAnimationSuppressed(false),
       mSupportTranslucency(false),
-      mMouseTransparent(false)
+      mMouseTransparent(false),
+      mHasRemoteContent(false)
   {
   }
 
   nsWindowType  mWindowType;
   nsBorderStyle mBorderStyle;
   nsPopupType   mPopupHint;
   nsPopupLevel  mPopupLevel;
   // B2G multi-screen support. Screen ID is for differentiating screens of
@@ -126,11 +127,12 @@ struct nsWidgetInitData {
   bool          mIsDragPopup;  // true for drag feedback panels
   // true if window creation animation is suppressed, e.g. for session restore
   bool          mIsAnimationSuppressed;
   // true if the window should support an alpha channel, if available.
   bool          mSupportTranslucency;
   // true if the window should be transparent to mouse events. Currently this is
   // only valid for eWindowType_popup widgets
   bool          mMouseTransparent;
+  bool          mHasRemoteContent;
 };
 
 #endif // nsWidgetInitData_h__