Use OverlayContainer in framework.

osu.Game/Overlays/ChatConsole.cs

@@ -20,7 +20,7 @@ using osu.Game.Online.Chat.Display;
 
 namespace osu.Game.Overlays
 {
-    public class ChatConsole : Overlay
+    public class ChatConsole : OverlayContainer
     {
         private ChannelDisplay channelDisplay;
 

osu.Game/Overlays/Options.cs

@@ -6,13 +6,14 @@ using OpenTK.Graphics;
 using OpenTK.Input;
 using osu.Framework;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Drawables;
 using osu.Framework.Graphics.Transformations;
 using osu.Framework.Input;
 
 namespace osu.Game.Overlays
 {
-    public class Options : Overlay
+    public class Options : OverlayContainer
     {
         private const float width = 300;
 

osu.Game/Overlays/Overlay.cs

@@ -1,53 +0,0 @@
-using osu.Framework;
-using osu.Framework.Graphics.Containers;
-
-namespace osu.Game.Overlays
-{
-    /// <summary>
-    /// An element which starts hidden and can be toggled to visible.
-    /// </summary>
-    public abstract class Overlay : Container, IStateful<Visibility>
-    {
-        public override void Load(BaseGame game)
-        {
-            base.Load(game);
-
-            //TODO: init code using Alpha or IsVisible override to ensure we don't call Load on children before we first get unhidden.
-            PopOut();
-            Flush();
-        }
-
-        private Visibility state;
-        public Visibility State
-        {
-            get { return state; }
-            set
-            {
-                if (value == state) return;
-                state = value;
-
-                switch (value)
-                {
-                    case Visibility.Hidden:
-                        PopOut();
-                        break;
-                    case Visibility.Visible:
-                        PopIn();
-                        break;
-                }
-            }
-        }
-
-        protected abstract void PopIn();
-
-        protected abstract void PopOut();
-
-        public void ToggleVisibility() => State = (State == Visibility.Visible ? Visibility.Hidden : Visibility.Visible);
-    }
-
-    public enum Visibility
-    {
-        Hidden,
-        Visible
-    }
-}

osu.Game/Overlays/Toolbar.cs

@@ -15,7 +15,7 @@ using osu.Game.Graphics;
 
 namespace osu.Game.Overlays
 {
-    public class Toolbar : Overlay
+    public class Toolbar : OverlayContainer
     {
         private const float height = 50;
 

osu.Game/osu.Game.csproj

@@ -156,7 +156,6 @@
     <Compile Include="OsuGameBase.cs" />
     <Compile Include="Overlays\ChatConsole.cs" />
     <Compile Include="Overlays\Options.cs" />
-    <Compile Include="Overlays\Overlay.cs" />
     <Compile Include="Overlays\Toolbar.cs" />
     <Compile Include="Overlays\ToolbarButton.cs" />
     <Compile Include="Overlays\ToolbarModeButton.cs" />