I have an event that changes the Tag associated with my NDrawingDocument, but when I undo the Event it doesn't revert the Tag to it's previous state. Is there something I am missing?

I ask because I have Shapes that are utilizing this behavior properly using the NShape.Drawing.StartTransaction/HistoryService.Commit paradigm.

Is there something I should be doing differently?

Here is my code snippet.


_form.document.StartTransaction("UpdateFormatProperties");
_form.document.Tag = object.Clone();
//Do some other stuff to the document.
_form.document.HistoryService.Commit();