I am using the diagram tool and it is bound to a collection of shapes which represent business objects. The collecion derives from GraphSourceBase<LocationNodeViewModel, LinkViewModelBase<T>> and a DataTemplateSelector is used to set the shape. All business shapes are not editable, nor are the connections between them. I also need to add blocks of text anywhere in the diagram as text annotations. But, when I set the ActiveTool to TextTool, an exception is thrown. It appears that the textblock cannot be added to the bound collection. If I unbind the diagram from the collection, the text will be added just fine.
Do I need to customize the shape that represents the text block being added? And does this require customizing the TextTool itself, or is there some other preferred approach to achieving this? I have recreated this issue in a sample project if needed.
Much thanks in advance,