From ce956d7fd41feb9ca9e3a3201bad7834756302dd Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Mon, 19 Nov 2018 16:19:56 +0900
Subject: [PATCH] Fix exception when order of objects changes

---
 osu.Game.Rulesets.Mania/Edit/ManiaSelectionBox.cs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/osu.Game.Rulesets.Mania/Edit/ManiaSelectionBox.cs b/osu.Game.Rulesets.Mania/Edit/ManiaSelectionBox.cs
index 83a04639eb..9dd0d617c4 100644
--- a/osu.Game.Rulesets.Mania/Edit/ManiaSelectionBox.cs
+++ b/osu.Game.Rulesets.Mania/Edit/ManiaSelectionBox.cs
@@ -6,6 +6,7 @@ using osu.Framework.Allocation;
 using osu.Framework.Input.Events;
 using osu.Framework.Timing;
 using osu.Game.Rulesets.Mania.Objects;
+using osu.Game.Rulesets.UI;
 using osu.Game.Rulesets.UI.Scrolling;
 using osu.Game.Screens.Edit.Compose.Components;
 using OpenTK;
@@ -34,7 +35,7 @@ namespace osu.Game.Rulesets.Mania.Edit
             {
                 var hitObject = blueprint.HitObject;
 
-                var objectParent = hitObject.Parent;
+                var objectParent = (HitObjectContainer)hitObject.Parent;
 
                 // Using the hitobject position is required since AdjustPosition can be invoked multiple times per frame
                 // without the position having been updated by the parenting ScrollingHitObjectContainer
@@ -49,10 +50,14 @@ namespace osu.Game.Rulesets.Mania.Edit
                 else
                     targetPosition = hitObject.Position.Y;
 
+                objectParent.Remove(hitObject);
+
                 hitObject.HitObject.StartTime = scrollingInfo.Algorithm.TimeAt(targetPosition,
                     editorClock.CurrentTime,
                     scrollingInfo.TimeRange.Value,
                     objectParent.DrawHeight);
+
+                objectParent.Add(hitObject);
             }
 
             adjustColumn(dragEvent);