From c15aa6e1003ac68593a6b81853a2e1938d106dda Mon Sep 17 00:00:00 2001
From: Dirkster99 <Dirk.Bahle@gmx.de>
Date: Wed, 20 Nov 2019 19:06:40 +0100
Subject: [PATCH] HotFix on issue to void crash caused by threading issue
 https://github.com/Dirkster99/AvalonDock/issues/90

---
 .../Controls/LayoutAnchorableTabItem.cs                   | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableTabItem.cs b/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableTabItem.cs
index 08c95a44..5aeb512b 100644
--- a/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableTabItem.cs
+++ b/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableTabItem.cs
@@ -195,7 +195,13 @@ protected override void OnMouseEnter( MouseEventArgs e )
           return;
 
         var childrenList = container.Children.ToList();
-        containerPane.MoveChild( childrenList.IndexOf( _draggingItem.Model ), childrenList.IndexOf( model ) );
+
+        // Hotfix to avoid crash caused by a likely threading issue Back in the containerPane.
+        var oldIndex = childrenList.IndexOf( _draggingItem.Model ); 
+                var newIndex = childrenList.IndexOf( model );
+        
+        if (newIndex < containerPane.ChildrenCount && oldIndex > -1)
+          containerPane.MoveChild( oldIndex, newIndex );
       }
     }