Rearrange things somewhat

osu.Game/Graphics/UserInterface/OsuTabControl.cs

@@ -0,0 +1,24 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using osu.Framework.Graphics.UserInterface.Tab;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    public class OsuTabControl<T> : TabControl<T>
+    {
+        protected override TabDropDownMenu<T> CreateDropDownMenu() => new OsuTabDropDownMenu<T>();
+
+        protected override TabItem<T> CreateTabItem(T value) => new OsuTabItem<T> { Value = value };
+
+        public OsuTabControl(float offset = 0) : base(offset)
+        {
+            if (!typeof(T).IsEnum)
+                throw new InvalidOperationException("OsuTabControl only supports enums as the generic type argument");
+
+            foreach (var val in (T[])Enum.GetValues(typeof(T)))
+                AddTab(val);
+        }
+    }
+}