When you use the ConnectionDataSource of RadDiagram to data bind an SqlDataSource to its connections, a NullReferenceException is thrown. You can avoid this issue by using ConnectionDataSourceId instead.
RadDiagram throws a NullReferenceException when you bind it declaratively and place it in the ItemTemplate of a data bound control, for example a Repeater.
When you change the beginning or the end of an existing RadDiagram connection and call the client-side save() method, the exported data for the modified connection will not be updated.
Does not matter what value is set to the Connection's StartCap/EndCap properties, the ends of the connection are rendered as if the value of these properties is "None".