Guys, I need this crash resolved ASAP;

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Exception Error: 100 : Timestamp: 6/7/2010 9:18:49 PM
Message: HandlingInstanceID: 69d2f66e-1ce4-412b-b00f-7230c67c7218
An exception of type 'System.InvalidOperationException' occurred and was caught.
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06/07/2010 17:18:49
Type : System.InvalidOperationException, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
Message : Specified element is already the logical child of another element. Disconnect it first.
Source : PresentationFramework
Help link :
Data : System.Collections.ListDictionaryInternal
TargetSite : Void ChangeLogicalParent(System.Windows.DependencyObject)
Stack Trace :    at System.Windows.FrameworkElement.ChangeLogicalParent(DependencyObject newParent)
   at MS.Internal.FrameworkObject.ChangeLogicalParent(DependencyObject newParent)
   at System.Windows.FrameworkElement.AddLogicalChild(Object child)
   at Infragistics.Windows.DockManager.XamDockManager.AddLogicalChildInternal(DependencyObject logicalChild)
   at Infragistics.Windows.DockManager.XamDockManager.PanesCollection.OnDockedPanesChanged(Object sender, NotifyCollectionChangedEventArgs e)
   at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
   at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at Infragistics.Windows.Helpers.ObservableCollectionExtended`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at Infragistics.Windows.DockManager.QueuedObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at Infragistics.Windows.Helpers.ObservableCollectionExtended`1.EndUpdate()
   at Infragistics.Windows.Helpers.ObservableCollectionExtended`1.ReInitialize(IList`1 collection)
   at Infragistics.Windows.DockManager.XamDockManager.PanesCollection.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
   at Infragistics.Windows.Helpers.ObservableCollectionExtended`1.InsertItem(Int32 index, T item)
   at System.Collections.ObjectModel.Collection`1.Add(T item)
   at Infragistics.Windows.DockManager.Dragging.DragManager.CreateWindowBeingDragged(Point location, Size size)
   at Infragistics.Windows.DockManager.Dragging.FloatPaneAction.PerformAction(DragManager dragManager, Boolean isPreview)
   at Infragistics.Windows.DockManager.Dragging.DragManager.ProcessDragMove(MouseEventArgs e)
   at Infragistics.Windows.DockManager.Dragging.DragManager.StartDrag(FrameworkElement element, Point mouseDownPosition, MouseEventArgs e, Boolean processMove)
   at Infragistics.Windows.DockManager.Dragging.DragManager.OnPendingDragElementMouseMove(Object sender, MouseEventArgs e)
   at System.Windows.Input.MouseEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
   at System.Windows.Input.InputManager.ProcessStagingArea()
   at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
   at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
   at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
   at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at System.Windows.Interop.HwndSource.InputFilterMessage(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, Boolean isSingleParameter)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
   at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
   at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter)
   at System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
   at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
   at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
   at System.Windows.Threading.Dispatcher.Run()
   at System.Windows.Application.RunDispatcher(Object ignore)
   at System.Windows.Application.RunInternal(Window window)
   at System.Windows.Application.Run(Window window)
   at System.Windows.Application.Run()
   at OCC600.Infrastructure.Shell.App.Main()

This happened when I tried to drag a ContentPane from a floating SplitPane group to a tabbed document. That is two ContentPanes were grouped together in a SplitPane.  When I attempted to drag one of them out of the SplitPane, I got the crash.

TIA.

Klaus

TIA.

Klaus