From e2d11af4ef133317810f0bb0bd39419ff1183c74 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Tue, 13 Feb 2018 19:59:32 +0900
Subject: [PATCH] Fix incorrect MusicController drag handling

---
 osu.Game/Overlays/MusicController.cs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/osu.Game/Overlays/MusicController.cs b/osu.Game/Overlays/MusicController.cs
index b3140d8bd0..74f6e4435d 100644
--- a/osu.Game/Overlays/MusicController.cs
+++ b/osu.Game/Overlays/MusicController.cs
@@ -2,7 +2,6 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System;
-using System.Diagnostics;
 using System.Linq;
 using System.Threading.Tasks;
 using osu.Framework.Allocation;
@@ -65,9 +64,12 @@ public MusicController()
             AlwaysPresent = true;
         }
 
+        private Vector2 dragStart;
+
         protected override bool OnDragStart(InputState state)
         {
             base.OnDragStart(state);
+            dragStart = state.Mouse.Position;
             return true;
         }
 
@@ -75,9 +77,7 @@ protected override bool OnDrag(InputState state)
         {
             if (base.OnDrag(state)) return true;
 
-            Trace.Assert(state.Mouse.PositionMouseDown != null, "state.Mouse.PositionMouseDown != null");
-
-            Vector2 change = state.Mouse.Position - state.Mouse.PositionMouseDown.Value;
+            Vector2 change = state.Mouse.Position - dragStart;
 
             // Diminish the drag distance as we go further to simulate "rubber band" feeling.
             change *= change.Length <= 0 ? 0 : (float)Math.Pow(change.Length, 0.7f) / change.Length;