Create new OsuScreenStack for use in Multiplayer

osu.Game/Screens/Multi/Multiplayer.cs

@@ -50,9 +50,6 @@ namespace osu.Game.Screens.Multi
         [Cached(Type = typeof(IRoomManager))]
         private RoomManager roomManager;
 
-        [Cached]
-        private BackgroundScreenStack backgroundScreenStack;
-
         [Resolved]
         private OsuGameBase game { get; set; }
 
@@ -100,12 +97,7 @@ namespace osu.Game.Screens.Multi
                         Padding = new MarginPadding { Top = Header.HEIGHT },
                         Children = new CompositeDrawable[]
                         {
-                            new ParallaxContainer
+                            screenStack = new OsuScreenStack(loungeSubScreen = new LoungeSubScreen()) { RelativeSizeAxes = Axes.Both },
-                            {
-                                RelativeSizeAxes = Axes.Both,
-                                Child = backgroundScreenStack = new BackgroundScreenStack { RelativeSizeAxes = Axes.Both },
-                            },
-                            screenStack = new ScreenStack(loungeSubScreen = new LoungeSubScreen()) { RelativeSizeAxes = Axes.Both },
                         }
                     },
                     new Header(screenStack),

osu.Game/Screens/OsuScreenStack.cs

@@ -0,0 +1,28 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Screens;
+using osu.Game.Graphics.Containers;
+using osu.Game.Screens.Multi.Lounge;
+
+namespace osu.Game.Screens
+{
+    public class OsuScreenStack : ScreenStack
+    {
+        [Cached]
+        private BackgroundScreenStack backgroundScreenStack;
+
+        public OsuScreenStack(IScreen baseScreen)
+            : base(baseScreen)
+        {
+            backgroundScreenStack = new BackgroundScreenStack { RelativeSizeAxes = Axes.Both };
+            InternalChild = new ParallaxContainer
+            {
+                RelativeSizeAxes = Axes.Both,
+                Child = backgroundScreenStack,
+            };
+        }
+    }
+}