diff --git a/gfx/tests/gtest/TestCompositor.cpp b/gfx/tests/gtest/TestCompositor.cpp
index 22bfd110edff..7a2556ae0276 100644
--- a/gfx/tests/gtest/TestCompositor.cpp
+++ b/gfx/tests/gtest/TestCompositor.cpp
@@ -82,7 +82,6 @@ public:
   virtual LayoutDeviceIntPoint WidgetToScreenOffset() override { return LayoutDeviceIntPoint(0, 0); }
   NS_IMETHOD              DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
                                         nsEventStatus& aStatus) override { return NS_OK; }
-  NS_IMETHOD              CaptureRollupEvents(nsIRollupListener * aListener, bool aDoCapture) override { return NS_OK; }
   NS_IMETHOD_(void)       SetInputContext(const InputContext& aContext,
                                           const InputContextAction& aAction) override {}
   NS_IMETHOD_(InputContext) GetInputContext() override { abort(); }
diff --git a/widget/PuppetWidget.h b/widget/PuppetWidget.h
index f727d348974c..3d2c907cc8bf 100644
--- a/widget/PuppetWidget.h
+++ b/widget/PuppetWidget.h
@@ -147,10 +147,6 @@ public:
                              const mozilla::Maybe<ZoomConstraints>& aConstraints) override;
   bool AsyncPanZoomEnabled() const override;
 
-  NS_IMETHOD CaptureRollupEvents(nsIRollupListener* aListener,
-                                 bool aDoCapture) override
-  { return NS_ERROR_UNEXPECTED; }
-
   NS_IMETHOD_(bool)
   ExecuteNativeKeyBinding(NativeKeyBindingsType aType,
                           const mozilla::WidgetKeyboardEvent& aEvent,
diff --git a/widget/android/nsWindow.h b/widget/android/nsWindow.h
index 24f5f050ebb4..7162f477cc8b 100644
--- a/widget/android/nsWindow.h
+++ b/widget/android/nsWindow.h
@@ -181,9 +181,6 @@ public:
     NS_IMETHOD SetTitle(const nsAString& aTitle) override { return NS_OK; }
     NS_IMETHOD SetIcon(const nsAString& aIconSpec) override { return NS_OK; }
     NS_IMETHOD CaptureMouse(bool aCapture) override { return NS_ERROR_NOT_IMPLEMENTED; }
-    NS_IMETHOD CaptureRollupEvents(nsIRollupListener *aListener,
-                                   bool aDoCapture) override { return NS_ERROR_NOT_IMPLEMENTED; }
-
     NS_IMETHOD GetAttention(int32_t aCycleCount) override { return NS_ERROR_NOT_IMPLEMENTED; }
     NS_IMETHOD BeginResizeDrag(mozilla::WidgetGUIEvent* aEvent,
                                int32_t aHorizontal,
diff --git a/widget/cocoa/nsChildView.h b/widget/cocoa/nsChildView.h
index 9b6df9033cd1..f609cfef8cdf 100644
--- a/widget/cocoa/nsChildView.h
+++ b/widget/cocoa/nsChildView.h
@@ -362,7 +362,6 @@ public:
   NS_IMETHOD        SetCursor(nsCursor aCursor) override;
   NS_IMETHOD        SetCursor(imgIContainer* aCursor, uint32_t aHotspotX, uint32_t aHotspotY) override;
 
-  NS_IMETHOD        CaptureRollupEvents(nsIRollupListener * aListener, bool aDoCapture) override;
   NS_IMETHOD        SetTitle(const nsAString& title) override;
 
   NS_IMETHOD        GetAttention(int32_t aCycleCount) override;
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
index 7b62a193cd5c..9eb09a24cbea 100644
--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -1613,13 +1613,6 @@ LayoutDeviceIntPoint nsChildView::WidgetToScreenOffset()
   NS_OBJC_END_TRY_ABORT_BLOCK_RETURN(LayoutDeviceIntPoint(0,0));
 }
 
-NS_IMETHODIMP nsChildView::CaptureRollupEvents(nsIRollupListener * aListener,
-                                               bool aDoCapture)
-{
-  // this never gets called, only top-level windows can be rollup widgets
-  return NS_OK;
-}
-
 NS_IMETHODIMP nsChildView::SetTitle(const nsAString& title)
 {
   // child views don't have titles
diff --git a/widget/cocoa/nsCocoaWindow.h b/widget/cocoa/nsCocoaWindow.h
index f5759c0acba6..27776b1e07eb 100644
--- a/widget/cocoa/nsCocoaWindow.h
+++ b/widget/cocoa/nsCocoaWindow.h
@@ -305,7 +305,8 @@ public:
                                           LayerManagerPersistence aPersistence = LAYER_MANAGER_CURRENT) override;
     NS_IMETHOD DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
                              nsEventStatus& aStatus) override;
-    NS_IMETHOD CaptureRollupEvents(nsIRollupListener * aListener, bool aDoCapture) override;
+    virtual void CaptureRollupEvents(nsIRollupListener * aListener,
+                                     bool aDoCapture) override;
     NS_IMETHOD GetAttention(int32_t aCycleCount) override;
     virtual bool HasPendingInputEvent() override;
     virtual nsTransparencyMode GetTransparencyMode() override;
diff --git a/widget/cocoa/nsCocoaWindow.mm b/widget/cocoa/nsCocoaWindow.mm
index 084b3c43bf27..6da31fdc8cbe 100644
--- a/widget/cocoa/nsCocoaWindow.mm
+++ b/widget/cocoa/nsCocoaWindow.mm
@@ -2060,9 +2060,11 @@ nsMenuBarX* nsCocoaWindow::GetMenuBar()
   return mMenuBar;
 }
 
-NS_IMETHODIMP nsCocoaWindow::CaptureRollupEvents(nsIRollupListener* aListener, bool aDoCapture)
+void
+nsCocoaWindow::CaptureRollupEvents(nsIRollupListener* aListener,
+                                   bool aDoCapture)
 {
-  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
 
   gRollupListener = nullptr;
   
@@ -2099,9 +2101,7 @@ NS_IMETHODIMP nsCocoaWindow::CaptureRollupEvents(nsIRollupListener* aListener, b
       [mWindow setLevel:NSModalPanelWindowLevel];
   }
   
-  return NS_OK;
-
-  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
+  NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 
 NS_IMETHODIMP nsCocoaWindow::GetAttention(int32_t aCycleCount)
diff --git a/widget/gonk/nsWindow.h b/widget/gonk/nsWindow.h
index 38a593e80748..6106982f938c 100644
--- a/widget/gonk/nsWindow.h
+++ b/widget/gonk/nsWindow.h
@@ -92,12 +92,6 @@ public:
                                                 uint32_t aPointerOrientation,
                                                 nsIObserver* aObserver) override;
 
-    NS_IMETHOD CaptureRollupEvents(nsIRollupListener *aListener,
-                                   bool aDoCapture)
-    {
-        return NS_ERROR_NOT_IMPLEMENTED;
-    }
-
     virtual nsresult MakeFullScreen(
         bool aFullScreen, nsIScreen* aTargetScreen = nullptr) override;
 
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
index 7ce83b07aa11..6a7905273467 100644
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -1890,15 +1890,15 @@ nsWindow::CaptureMouse(bool aCapture)
     return NS_OK;
 }
 
-NS_IMETHODIMP
+void
 nsWindow::CaptureRollupEvents(nsIRollupListener *aListener,
                               bool               aDoCapture)
 {
     if (!mGdkWindow)
-        return NS_OK;
+        return;
 
     if (!mContainer)
-        return NS_ERROR_FAILURE;
+        return;
 
     LOG(("CaptureRollupEvents %p %i\n", this, int(aDoCapture)));
 
@@ -1921,8 +1921,6 @@ nsWindow::CaptureRollupEvents(nsIRollupListener *aListener,
         gtk_grab_remove(GTK_WIDGET(mContainer));
         gRollupListener = nullptr;
     }
-
-    return NS_OK;
 }
 
 NS_IMETHODIMP
diff --git a/widget/gtk/nsWindow.h b/widget/gtk/nsWindow.h
index 54d502d9afad..cfd4c7aece07 100644
--- a/widget/gtk/nsWindow.h
+++ b/widget/gtk/nsWindow.h
@@ -145,7 +145,7 @@ public:
     virtual void       SetWindowClass(const nsAString& xulWinType) override;
     virtual LayoutDeviceIntPoint WidgetToScreenOffset() override;
     NS_IMETHOD         CaptureMouse(bool aCapture) override;
-    NS_IMETHOD         CaptureRollupEvents(nsIRollupListener *aListener,
+    virtual void       CaptureRollupEvents(nsIRollupListener *aListener,
                                            bool aDoCapture) override;
     NS_IMETHOD         GetAttention(int32_t aCycleCount) override;
     virtual nsresult   SetWindowClipRegion(const nsTArray<LayoutDeviceIntRect>& aRects,
diff --git a/widget/nsBaseWidget.h b/widget/nsBaseWidget.h
index 4b632bb49a7d..5a2a3eda0685 100644
--- a/widget/nsBaseWidget.h
+++ b/widget/nsBaseWidget.h
@@ -141,6 +141,8 @@ public:
 
   // nsIWidget interface
   NS_IMETHOD              CaptureMouse(bool aCapture) override;
+  virtual void            CaptureRollupEvents(nsIRollupListener* aListener,
+                                              bool aDoCapture) override {}
   virtual nsIWidgetListener*  GetWidgetListener() override;
   virtual void            SetWidgetListener(nsIWidgetListener* alistener) override;
   virtual void            Destroy() override;
diff --git a/widget/nsIWidget.h b/widget/nsIWidget.h
index 4034e5fb68c4..36d3ac04d70b 100644
--- a/widget/nsIWidget.h
+++ b/widget/nsIWidget.h
@@ -1395,7 +1395,8 @@ class nsIWidget : public nsISupports
      * @param aDoCapture true enables capture, false disables capture
      *
      */
-    NS_IMETHOD CaptureRollupEvents(nsIRollupListener* aListener, bool aDoCapture) = 0;
+    virtual void CaptureRollupEvents(nsIRollupListener* aListener,
+                                     bool aDoCapture) = 0;
 
     /**
      * Bring this window to the user's attention.  This is intended to be a more
diff --git a/widget/uikit/nsWindow.h b/widget/uikit/nsWindow.h
index c936f5cd3020..cb18c090692c 100644
--- a/widget/uikit/nsWindow.h
+++ b/widget/uikit/nsWindow.h
@@ -80,10 +80,6 @@ public:
     virtual nsresult ConfigureChildren(const nsTArray<Configuration>& aConfigurations) override;
     NS_IMETHOD DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
                              nsEventStatus& aStatus) override;
-    NS_IMETHOD CaptureRollupEvents(nsIRollupListener * aListener,
-                                   bool aDoCapture) override {
-        return NS_ERROR_NOT_IMPLEMENTED;
-    }
 
     void WillPaintWindow();
     bool PaintWindow(LayoutDeviceIntRegion aRegion);
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
index 5eb95442ec4a..844c60357c05 100644
--- a/widget/windows/nsWindow.cpp
+++ b/widget/windows/nsWindow.cpp
@@ -3565,8 +3565,8 @@ NS_IMETHODIMP nsWindow::CaptureMouse(bool aCapture)
  *
  **************************************************************/
 
-NS_IMETHODIMP nsWindow::CaptureRollupEvents(nsIRollupListener * aListener,
-                                            bool aDoCapture)
+void
+nsWindow::CaptureRollupEvents(nsIRollupListener* aListener, bool aDoCapture)
 {
   if (aDoCapture) {
     gRollupListener = aListener;
@@ -3579,8 +3579,6 @@ NS_IMETHODIMP nsWindow::CaptureRollupEvents(nsIRollupListener * aListener,
     sProcessHook = false;
     UnregisterSpecialDropdownHooks();
   }
-
-  return NS_OK;
 }
 
 /**************************************************************
diff --git a/widget/windows/nsWindow.h b/widget/windows/nsWindow.h
index 4275965d0494..9507f0c6e240 100644
--- a/widget/windows/nsWindow.h
+++ b/widget/windows/nsWindow.h
@@ -167,7 +167,7 @@ public:
                                         nsEventStatus& aStatus) override;
   virtual void            EnableDragDrop(bool aEnable) override;
   NS_IMETHOD              CaptureMouse(bool aCapture) override;
-  NS_IMETHOD              CaptureRollupEvents(nsIRollupListener * aListener,
+  virtual void            CaptureRollupEvents(nsIRollupListener* aListener,
                                               bool aDoCapture) override;
   NS_IMETHOD              GetAttention(int32_t aCycleCount) override;
   virtual bool            HasPendingInputEvent() override;