Index: Core/Common/src/Core.Common.Gui/Forms/ViewHost/DocumentViewController.cs
===================================================================
diff -u -r6fc42a91bd445cd4896eb833ffb2fcd88a54cdbe -r555a6c0604e1c4aa7ff67bb74e4d49884d333a14
--- Core/Common/src/Core.Common.Gui/Forms/ViewHost/DocumentViewController.cs	(.../DocumentViewController.cs)	(revision 6fc42a91bd445cd4896eb833ffb2fcd88a54cdbe)
+++ Core/Common/src/Core.Common.Gui/Forms/ViewHost/DocumentViewController.cs	(.../DocumentViewController.cs)	(revision 555a6c0604e1c4aa7ff67bb74e4d49884d333a14)
@@ -177,9 +177,15 @@
         {
             ViewInfo viewInfo = viewInfos.FirstOrDefault(vi => vi.ViewType == view.GetType());
 
-            return viewInfo != null
-                   && (Equals(viewInfo.GetViewData(data), view.Data) ||
-                       viewInfo.CloseForData(view, data));
+            if (viewInfo == null)
+            {
+                return false;
+            }
+
+            bool isViewData = data.GetType().Implements(viewInfo.DataType)
+                              && Equals(viewInfo.GetViewData(data), view.Data);
+
+            return isViewData || viewInfo.CloseForData(view, data);
         }
 
         private void ViewHostOnViewClosed(object sender, ViewChangeEventArgs viewChangeEventArgs)