--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -1931,19 +1931,20 @@ nsBaseWidget::GetWidgetScreen()
   nsCOMPtr<nsIScreenManager> screenManager;
   screenManager = do_GetService("@mozilla.org/gfx/screenmanager;1");
   if (!screenManager) {
     return nullptr;
   }
 
   LayoutDeviceIntRect bounds;
   GetScreenBounds(bounds);
+  DesktopIntRect deskBounds = RoundedToInt(bounds / GetDesktopToDeviceScale());
   nsCOMPtr<nsIScreen> screen;
-  screenManager->ScreenForRect(bounds.x, bounds.y,
-                               bounds.width, bounds.height,
+  screenManager->ScreenForRect(deskBounds.x, deskBounds.y,
+                               deskBounds.width, deskBounds.height,
                                getter_AddRefs(screen));
   return screen.forget();
 }
 
 nsresult
 nsIWidget::SynthesizeNativeTouchTap(LayoutDeviceIntPoint aPoint, bool aLongTap,
                                     nsIObserver* aObserver)
 {