Rearrange things somewhat

osu.Game/Graphics/UserInterface/OsuTabDropDownMenu.cs

@@ -0,0 +1,56 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using OpenTK;
+using OpenTK.Graphics;
+using osu.Framework.Allocation;
+using osu.Framework.Extensions.Color4Extensions;
+using osu.Framework.Graphics.Primitives;
+using osu.Framework.Graphics.Transforms;
+using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Graphics.UserInterface.Tab;
+using osu.Game.Graphics;
+using osu.Game.Screens.Select.Filter;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    public class OsuTabDropDownMenu<T> : TabDropDownMenu<T>
+    {
+        public override float HeaderWidth => 14;
+        public override float HeaderHeight => 24;
+
+        protected override DropDownHeader CreateHeader() => new OsuTabDropDownHeader();
+
+        protected override DropDownMenuItem<T> CreateDropDownItem(string key, T value) => new OsuTabDropDownMenuItem<T>(key, value);
+
+        public OsuTabDropDownMenu()
+        {
+            MaxDropDownHeight = int.MaxValue;
+            ContentContainer.CornerRadius = 4;
+            ContentBackground.Colour = Color4.Black.Opacity(0.9f);
+            ScrollContainer.ScrollDraggerVisible = false;
+            DropDownItemsContainer.Padding = new MarginPadding { Left = 5, Bottom = 7, Right = 5, Top = 7 };
+        }
+
+        protected override void AnimateOpen()
+        {
+            ContentContainer.FadeIn(300, EasingTypes.OutQuint);
+        }
+
+        protected override void AnimateClose()
+        {
+            ContentContainer.FadeOut(300, EasingTypes.OutQuint);
+        }
+
+        protected override void UpdateContentHeight()
+        {
+            ContentContainer.ResizeTo(new Vector2(1, State == DropDownMenuState.Opened ? ContentHeight : 0), 300, EasingTypes.OutQuint);
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            Header.Colour = typeof(T) == typeof(SortMode) ? colours.GreenLight : colours.Blue;
+        }
+    }
+}