Hi,

We are getting an unhandled exception from MindFusion.Diagramming.Wpf.dll when performing following operation.

Our application is synchronized with the server and when any changes happened in the server, all instances get its notification. Steps are:

1. Trying to create a link from a ShapeNode (link's destination is still diagram, I have not released the mouse yet) in first instance

2. From second instance, same ShapeNode has been deleted by another user.

3. In first instance that ShapeNode is got deleted but link is still visible without having source and destination node

4. When mouse button is released, link gone but when click on diagram getting following unhandled exception

[1540] Exception Source: MindFusion.Diagramming.Wpf
[1540] Exception Message: Object reference not set to an instance of an object.
[1540] Exception StackTrace:
[1540]    at MindFusion.Diagramming.Wpf.InteractionState.x8ec3b2360a655172(DiagramItem xccb63ca5f63dc470) 
[1540]    at MindFusion.Diagramming.Wpf.DiagramItem.StartModify(Point org, Int32 handle, InteractionState ist) 
[1540]    at MindFusion.Diagramming.Wpf.DiagramNode.StartModify(Point org, Int32 handle, InteractionState ist) 
[1540]    at MindFusion.Diagramming.Wpf.ShapeNode.StartModify(Point org, Int32 handle, InteractionState ist) 
[1540]    at MindFusion.Diagramming.Wpf.InteractionState.Start(Point point, Diagram diagram) 
[1540]    at MindFusion.Diagramming.Wpf.Behaviors.BehaviorBase.OnMouseMove(Point mousePosition) 
[1540]    at MindFusion.Diagramming.Wpf.Diagram.OnPreviewMouseMove(MouseEventArgs e) 
[1540]    at System.Windows.UIElement.OnPreviewMouseMoveThunk(Object sender, MouseEventArgs e) 
[1540]    at System.Windows.Input.MouseEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget) 
[1540]    at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target) 
[1540]    at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs) 
[1540]    at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised) 
[1540]    at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args) 
[1540]    at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted) 
[1540]    at System.Windows.Input.InputManager.ProcessStagingArea() 
[1540]    at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input) 
[1540]    at System.Windows.Input.MouseDevice.Synchronize() 
[1540]    at System.Windows.Input.MouseDevice.ChangeMouseCapture(IInputElement mouseCapture, IMouseInputProvider providerCapture, CaptureMode captureMode, Int32 timestamp) 
[1540]    at System.Windows.Input.MouseDevice.PreNotifyInput(Object sender, NotifyInputEventArgs e) 
[1540]    at System.Windows.Input.InputManager.ProcessStagingArea() 
[1540]    at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input) 
[1540]    at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport) 
[1540]    at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel) 
[1540]    at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) 
[1540]    at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) 
[1540]    at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) 
[1540]    at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o) 
[1540]    at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) 
[1540]    at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
[1540] <<<<<-----

And after that application crashed.

Please look in to this issue and let know the suggestion to solve this as soon as possible.


Regards,
Anshul