Let selection container handle manual selection changes

osu.Game/Graphics/Containers/SelectionCycleFillFlowContainer.cs

@@ -1,6 +1,8 @@
 // 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 System;
+using System.Collections.Generic;
 using osu.Framework;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -60,5 +62,34 @@ namespace osu.Game.Graphics.Containers
         }
 
         public T Selected => (selectedIndex >= 0 && selectedIndex < Count) ? this[selectedIndex.Value] : null;
+
+        private readonly Dictionary<T, Action<SelectionState>> handlerMap = new Dictionary<T, Action<SelectionState>>();
+
+        public override void Add(T drawable)
+        {
+            // This event is used to update selection state when modified within the drawable itself.
+            // It is added to a dictionary so that we can unsubscribe if the drawable is removed from this container
+            drawable.StateChanged += handlerMap[drawable] = state => selectionChanged(drawable, state);
+
+            base.Add(drawable);
+        }
+
+        public override bool Remove(T drawable)
+        {
+            if (!base.Remove(drawable))
+                return false;
+
+            drawable.StateChanged -= handlerMap[drawable];
+            handlerMap.Remove(drawable);
+            return true;
+        }
+
+        private void selectionChanged(T drawable, SelectionState state)
+        {
+            if (state == SelectionState.NotSelected)
+                Deselect();
+            else
+                Select(drawable);
+        }
     }
 }

osu.Game/Overlays/VolumeOverlay.cs

@@ -13,7 +13,6 @@ using osu.Framework.Input.Events;
 using osu.Framework.Threading;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
-using osu.Game.Graphics.UserInterface;
 using osu.Game.Input.Bindings;
 using osu.Game.Overlays.Volume;
 using osuTK;
@@ -92,10 +91,7 @@ namespace osu.Game.Overlays
             base.LoadComplete();
 
             foreach (var volumeMeter in volumeMeters)
-            {
                 volumeMeter.Bindable.ValueChanged += _ => Show();
-                volumeMeter.StateChanged += selected => volumeMeterSelectionChanged(volumeMeter, selected);
-            }
 
             muteButton.Current.ValueChanged += _ => Show();
         }
@@ -141,14 +137,6 @@ namespace osu.Game.Overlays
             return false;
         }
 
-        private void volumeMeterSelectionChanged(VolumeMeter meter, SelectionState state)
-        {
-            if (state == SelectionState.NotSelected)
-                volumeMeters.Deselect();
-            else
-                volumeMeters.Select(meter);
-        }
-
         private ScheduledDelegate popOutDelegate;
 
         public override void Show()

osu.Game/Screens/Play/GameplayMenuOverlay.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using Humanizer;
 using osu.Framework.Allocation;
 using osu.Framework.Extensions.Color4Extensions;
@@ -184,8 +183,6 @@ namespace osu.Game.Screens.Play
                 }
             };
 
-            button.StateChanged += selected => buttonSelectionChanged(button, selected);
-
             InternalButtons.Add(button);
         }
 
@@ -216,15 +213,6 @@ namespace osu.Game.Screens.Play
         public void OnReleased(GlobalAction action)
         {
         }
-
-        private void buttonSelectionChanged(DialogButton button, SelectionState state)
-        {
-            if (state == SelectionState.NotSelected)
-                InternalButtons.Deselect();
-            else
-                InternalButtons.Select(button);
-        }
-
         private void updateRetryCount()
         {
             // "You've retried 1,065 times in this session"