ArgumentNullException when docking Window

[Chris]

I received this exception when trying to dock a floating window. I have not been able to reproduce it since, however. Any suggestions of how I might track this down?

System.ArgumentNullException was unhandled
  HResult=-2147467261
  Message=Value cannot be null.
Parameter name: element
  Source=Telerik.Windows.Controls
  ParamName=element
  StackTrace:
       at Telerik.Windows.Controls.ChildrenOfTypeExtensions.<GetChildrenRecursive>d__3.MoveNext()
       at System.Linq.Enumerable.<OfTypeIterator>d__aa`1.MoveNext()
       at Telerik.Windows.Controls.Docking.ToolWindow.ActivatePane()
       at Telerik.Windows.Controls.Docking.ToolWindow.OnDragStart(Point globalMousePosition, Boolean isResize)
       at Telerik.Windows.Controls.WindowBase.Telerik.Windows.Controls.InternalWindow.IDragAware.OnDragStart(Point globalMousePosition, Boolean isResize)
       at Telerik.Windows.Controls.InternalWindow.WindowHostBase.OnDragStart(Point globalMousePosition, Boolean isResize)
       at Telerik.Windows.Controls.InternalWindow.ChromelessWindowHelper.TryBeginDragResize(IntPtr hwnd, Boolean resizing)
       at Telerik.Windows.Controls.InternalWindow.ChromelessWindowHelper.HandleMoving(IntPtr hwnd, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at Telerik.Windows.Controls.InternalWindow.ChromelessWindowHelper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at System.Windows.Interop.HwndSource.PublicHooksFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
       at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
  InnerException:

[Kalin]

Hi Chris,

Can you please share some more details about the exact Docking setup (some sample code would be nice)? Do you use PaneSource or static RadPanes? Do manually activate panes at run time? Any additional information would really helpful. Also you can share a video demonstrating the exact scenario, so we can test it on our side.

I'm looking forward to hearing from you.

Regards,
Kalin
Telerik