I'm trying to put together a diagram sample. I based it on this: https://www.telerik.com/forums/issue-in-copy-and-paste-diagram-items as the report was about a stack trace similar to the one I'm experiencing and trying to track down:
System.ArgumentNullException HResult=0x80004003 Message=Value cannot be null. Parameter name: dataObject Source=Telerik.Windows.Controls.Diagrams StackTrace: at Telerik.Windows.Controls.Diagrams.DataTransferService.HandleDiagramElementDrop(DataObject dataObject)
It builds fine but when I run it, I get an empty window, even if I click on the launch button. I can see no errors at runtime. I've attached a ZIP file of the project.