diff --git a/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs b/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs
index 246de59e..0079a322 100644
--- a/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs
+++ b/source/Components/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorableFloatingWindowControl.cs
@@ -162,7 +162,8 @@ protected override void OnClosed( EventArgs e )
         root.FloatingWindows.Remove( _model );
       }
 
-      SetBinding(VisibilityProperty, string.Empty);
+      // We have to clear binding instead of creating a new empty binding.
+      BindingOperations.ClearBinding(_model, VisibilityProperty);
 
       _model.PropertyChanged -= new System.ComponentModel.PropertyChangedEventHandler( _model_PropertyChanged );
     }
diff --git a/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs b/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs
index dab25ed3..3e4ecf17 100644
--- a/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs
+++ b/source/Components/Xceed.Wpf.AvalonDock/DockingManager.cs
@@ -2400,7 +2400,8 @@ private void DockingManager_Unloaded( object sender, RoutedEventArgs e )
           //fw.Owner = null;
           fw.SetParentWindowToNull();
           fw.KeepContentVisibleOnClose = true;
-          fw.Close();
+          // To avoid calling Close method multiple times.
+          fw.InternalClose();
         }
          _fwList.Clear();