Index: Core/Common/src/Core.Common.Gui/Forms/ViewHost/AvalonDockViewHost.xaml
===================================================================
diff -u -r6ecd02f5f7c642d5624f1e52f528c51b1bf5ab3a -re783c11dba00e2ade7edfa1d9f49d9319b1b94eb
--- Core/Common/src/Core.Common.Gui/Forms/ViewHost/AvalonDockViewHost.xaml	(.../AvalonDockViewHost.xaml)	(revision 6ecd02f5f7c642d5624f1e52f528c51b1bf5ab3a)
+++ Core/Common/src/Core.Common.Gui/Forms/ViewHost/AvalonDockViewHost.xaml	(.../AvalonDockViewHost.xaml)	(revision e783c11dba00e2ade7edfa1d9f49d9319b1b94eb)
@@ -60,7 +60,7 @@
                         </xcad:LayoutDocumentPaneGroup>
                         <xcad:LayoutAnchorablePaneGroup>
                         <xcad:LayoutAnchorablePane>
-                            <xcad:LayoutAnchorable x:Name="dummyPanelA"></xcad:LayoutAnchorable>
+                            <xcad:LayoutAnchorable x:Name="dummyPanelA"/> <!-- Don't remove: dummy panel in order to prevent garbage collection by AvalonDock -->
                         </xcad:LayoutAnchorablePane>
                         </xcad:LayoutAnchorablePaneGroup>
                         <xcad:LayoutAnchorablePaneGroup x:Name="bottomLayoutAnchorablePaneGroup" DockHeight="200">
@@ -69,7 +69,7 @@
                     </xcad:LayoutPanel>
                     <xcad:LayoutAnchorablePaneGroup>
                         <xcad:LayoutAnchorablePane>
-                            <xcad:LayoutAnchorable x:Name="dummyPanelB"></xcad:LayoutAnchorable>
+                            <xcad:LayoutAnchorable x:Name="dummyPanelB"/> <!-- Don't remove: dummy panel in order to prevent garbage collection by AvalonDock -->
                         </xcad:LayoutAnchorablePane>
                     </xcad:LayoutAnchorablePaneGroup>
                     <xcad:LayoutAnchorablePaneGroup x:Name="rightLayoutAnchorablePaneGroup" Orientation="Vertical" DockWidth="220">
Index: Core/Common/src/Core.Common.Gui/Forms/ViewHost/AvalonDockViewHost.xaml.cs
===================================================================
diff -u -r6ecd02f5f7c642d5624f1e52f528c51b1bf5ab3a -re783c11dba00e2ade7edfa1d9f49d9319b1b94eb
--- Core/Common/src/Core.Common.Gui/Forms/ViewHost/AvalonDockViewHost.xaml.cs	(.../AvalonDockViewHost.xaml.cs)	(revision 6ecd02f5f7c642d5624f1e52f528c51b1bf5ab3a)
+++ Core/Common/src/Core.Common.Gui/Forms/ViewHost/AvalonDockViewHost.xaml.cs	(.../AvalonDockViewHost.xaml.cs)	(revision e783c11dba00e2ade7edfa1d9f49d9319b1b94eb)
@@ -171,7 +171,7 @@
             SetFocusToView(view);
 
             layoutAnchorable.Hiding += OnLayoutAnchorableHiding;
-            layoutAnchorable.Closing += OnLayoutAnchorableClosing;
+            layoutAnchorable.Closed += OnLayoutAnchorableClosed;
         }
 
         public void Remove(IView view)
@@ -195,7 +195,7 @@
             else if (toolViews.Contains(view))
             {
                 var layoutAnchorable = GetLayoutContent<LayoutAnchorable>(view);
-                layoutAnchorable.Hide();
+                layoutAnchorable.Close();
                 UpdateDockingManager();
             }
 
@@ -308,7 +308,7 @@
 
         private void OnLayoutDocumentClosing(object sender, CancelEventArgs e)
         {
-            var layoutDocument = (LayoutDocument)sender;
+            var layoutDocument = (LayoutDocument) sender;
             var view = GetView(layoutDocument.Content);
 
             if (ActiveDocumentView == view)
@@ -320,36 +320,35 @@
             }
         }
 
-        private void OnLayoutAnchorableHiding(object sender, CancelEventArgs eventArgs)
+        private void OnLayoutDocumentClosed(object sender, EventArgs e)
         {
-            var layoutAnchorable = (LayoutAnchorable)sender;
+            var layoutDocument = (LayoutDocument) sender;
 
-            layoutAnchorable.Hiding -= OnLayoutAnchorableHiding;
-            layoutAnchorable.Closing -= OnLayoutAnchorableClosing;
+            layoutDocument.Closing -= OnLayoutDocumentClosing;
+            layoutDocument.Closed -= OnLayoutDocumentClosed;
 
+            OnViewClosed(GetView(layoutDocument.Content));
+        }
+
+        private static void OnLayoutAnchorableHiding(object sender, CancelEventArgs eventArgs)
+        {
+            var layoutAnchorable = (LayoutAnchorable) sender;
+
             layoutAnchorable.Close();
-            OnViewClosed(GetView(layoutAnchorable.Content));
 
             eventArgs.Cancel = true;
         }
 
-        private void OnLayoutDocumentClosed(object sender, EventArgs e)
+        private void OnLayoutAnchorableClosed(object sender, EventArgs e)
         {
-            var layoutDocument = (LayoutDocument)sender;
+            var layoutAnchorable = (LayoutAnchorable) sender;
 
-            layoutDocument.Closing -= OnLayoutDocumentClosing;
-            layoutDocument.Closed -= OnLayoutDocumentClosed;
+            layoutAnchorable.Hiding -= OnLayoutAnchorableHiding;
+            layoutAnchorable.Closed -= OnLayoutAnchorableClosed;
 
-            OnViewClosed(GetView(layoutDocument.Content));
+            OnViewClosed(GetView(layoutAnchorable.Content));
         }
 
-        private void OnLayoutAnchorableClosing(object sender, CancelEventArgs e)
-        {
-            var layoutAnchorable = (LayoutAnchorable)sender;
-            layoutAnchorable.Hide();
-            e.Cancel = true;
-        }
-
         private void OnViewClosed(IView view)
         {
             if (documentViews.Contains(view))
@@ -404,7 +403,7 @@
 
         private void AddLayoutAnchorable(LayoutAnchorable layoutAnchorable, ToolViewLocation toolViewLocation)
         {
-            LayoutAnchorablePaneGroup layoutAnchorablePaneGroup = null;
+            LayoutAnchorablePaneGroup layoutAnchorablePaneGroup;
             switch (toolViewLocation)
             {
                 case ToolViewLocation.Left:
@@ -432,7 +431,7 @@
                     layoutAnchorablePaneGroup = rightLayoutAnchorablePaneGroup;
                     break;
                 default:
-                    throw new InvalidEnumArgumentException("toolViewLocation", (int)toolViewLocation, typeof(ToolViewLocation));
+                    throw new InvalidEnumArgumentException("toolViewLocation", (int) toolViewLocation, typeof(ToolViewLocation));
             }
 
             layoutAnchorablePaneGroup.Descendents()