I used Drag & drop framework with XamOrgChart and works fine, but I get an exception if I change ItemsSource of XamOrgChart a second time.

I changed ItemsSource in response of a click on a button, that opens a dialog, do some changes on database, and then reload data and set ItemsSource to reflect changes.

I get a System.NullReferenceException:

en Infragistics.DragDrop.DragDropManager.GetElementWithMouseCapture()    en Infragistics.DragDrop.DragDropManager.OnMouseLeftButtonDown(Object sender, MouseButtonEventArgs e)    en System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)    en System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)    en System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)    en System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)    en System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)    en System.Windows.UIElement.OnMouseDownThunk(Object sender, MouseButtonEventArgs e)    en System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)    en System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)    en System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)    en System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)    en System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)    en System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)    en System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)    en System.Windows.Input.InputManager.ProcessStagingArea()    en System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)    en System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)    en System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)    en System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)    en System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)    en MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)    en MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)    en System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)    en MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)    en System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)    en MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)    en MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)    en System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)    en System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)    en System.Windows.Window.ShowHelper(Object booleanBox)    en System.Windows.Window.Show()    en System.Windows.Window.ShowDialog()    en GrupoSTRL.MainWindow.cEncargoNuevo_Click(Object sender, RoutedEventArgs e) en d:\Proyectos\GrupoSTRL\Src\GrupoSTRL\MainWindow.xaml.cs:línea 101    en System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)    en System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)    en System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)    en System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)    en System.Windows.Controls.Primitives.ButtonBase.OnClick()    en Infragistics.Windows.Ribbon.ButtonTool.OnClick()    en System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)    en System.Windows.UIElement.OnMouseLeftButtonUpThunk(Object sender, MouseButtonEventArgs e)    en System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)    en System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)    en System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)    en System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)    en System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)    en System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e)    en System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)    en System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)    en System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)    en System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)    en System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)    en System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)    en System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)    en System.Windows.Input.InputManager.ProcessStagingArea()    en System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)    en System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)    en System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)    en System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)    en System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)    en MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)    en MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)    en System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)    en MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)    en System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)    en MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)    en MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)    en System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)    en System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)    en System.Windows.Threading.Dispatcher.Run()    en System.Windows.Application.RunDispatcher(Object ignore)    en System.Windows.Application.RunInternal(Window window)    en System.Windows.Application.Run(Window window)    en System.Windows.Application.Run()    en GrupoSTRL.App.Main() en d:\Proyectos\GrupoSTRL\Src\GrupoSTRL\obj\Debug\App.g.cs:línea 0    en System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)    en System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)    en Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()    en System.Threading.ThreadHelper.ThreadStart_Context(Object state)    en System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)    en System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)    en System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)    en System.Threading.ThreadHelper.ThreadStart()