From 82c2a6277168e00b0806bfb89ab7ebcea3e7e36f Mon Sep 17 00:00:00 2001
From: Dirkster99 <Dirk.Bahle@gmx.de>
Date: Fri, 27 Sep 2019 17:59:29 +0200
Subject: [PATCH] BugFix Candidate for
 https://github.com/Dirkster99/AvalonDock/issues/59

---
 .../Components/Xceed.Wpf.AvalonDock/DockingManager.cs | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs b/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs
index a5266b3a..671d06f8 100644
--- a/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs
+++ b/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs
@@ -2399,9 +2399,10 @@ private void DockingManager_Loaded( object sender, RoutedEventArgs e )
         }
         _fwHiddenList.Clear();
 
-        //load windows not already loaded!
-        foreach( var fw in Layout.FloatingWindows.Where( fw => !_fwList.Any( fwc => fwc.Model == fw ) ) )
-          _fwList.Add( CreateUIElementForModel( fw ) as LayoutFloatingWindowControl );
+        // load floating windows not already loaded! (issue #59)
+        List<LayoutFloatingWindow> items = new List<LayoutFloatingWindow>(Layout.FloatingWindows.Where(fw => !_fwList.Any(fwc => fwc.Model == fw)));
+        foreach (var fw in items)
+          _fwList.Add(CreateUIElementForModel(fw) as LayoutFloatingWindowControl);
 
         //create the overlaywindow if it's possible
         if( IsVisible )
@@ -2976,7 +2977,9 @@ private void RemoveViewFromLogicalChild( LayoutContent layoutContent )
 
     private void InternalSetActiveContent( object contentObject )
     {
-      var layoutContent = Layout.Descendents().OfType<LayoutContent>().FirstOrDefault( lc => lc == contentObject || lc.Content == contentObject );
+      // BugFix for first issue in #59
+      List<LayoutContent> list = Layout.Descendents().OfType<LayoutContent>().ToList();
+      var layoutContent = list.FirstOrDefault( lc => lc == contentObject || lc.Content == contentObject );
       _insideInternalSetActiveContent = true;
       Layout.ActiveContent = layoutContent;
       _insideInternalSetActiveContent = false;