There is a control responsible for visualizing the RadDiagramConnectors over the RadDiagramShapes. This control is defined in the Telerik.Windows.Controls.Diagrams assembly and it is called ConnectorsControl.
You can see how this control should be used in the default ControlTemplate targeting the RadDiagramShape. You can find it in our Telerik.Windows.Controls.Diagrams.xaml file.
If you have any further assistance, please open a new thread in our forum and ask your question there.
Thank you for understanding.
Pavel R. Pavlov
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