Better disabling of various controls

osu.Game/Screens/Multi/Components/DisableableTabControl.cs

@@ -0,0 +1,44 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System.Collections.Generic;
+using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Input.Events;
+
+namespace osu.Game.Screens.Multi.Components
+{
+    public abstract class DisableableTabControl<T> : TabControl<T>
+    {
+        public IEnumerable<T> DisabledItems
+        {
+            set
+            {
+                foreach (var item in value)
+                    (TabMap[item] as DisableableTabItem<T>)?.Disable();
+            }
+        }
+
+        protected abstract class DisableableTabItem<T> : TabItem<T>
+        {
+            protected DisableableTabItem(T value)
+                : base(value)
+            {
+            }
+
+            private bool isDisabled;
+
+            public void Disable()
+            {
+                Alpha = 0.2f;
+                isDisabled = true;
+            }
+
+            protected override bool OnClick(ClickEvent e)
+            {
+                if (isDisabled)
+                    return true;
+                return base.OnClick(e);
+            }
+        }
+    }
+}