diff --git a/ExtendedWPFToolkitSolution/Src/Xceed.Wpf.AvalonDock/Controls/LayoutFloatingWindowControl.cs b/ExtendedWPFToolkitSolution/Src/Xceed.Wpf.AvalonDock/Controls/LayoutFloatingWindowControl.cs
index f8231f19..d38b41fe 100644
--- a/ExtendedWPFToolkitSolution/Src/Xceed.Wpf.AvalonDock/Controls/LayoutFloatingWindowControl.cs
+++ b/ExtendedWPFToolkitSolution/Src/Xceed.Wpf.AvalonDock/Controls/LayoutFloatingWindowControl.cs
@@ -476,6 +476,10 @@ namespace Xceed.Wpf.AvalonDock.Controls
 
     internal void InternalClose()
     {
+      if( _internalCloseFlag )
+      {
+        return;
+      }
       _internalCloseFlag = true;
       Close();
     }