Setting diagram.UndoRedoService.UndoBufferSize to 0 after doing some undoable action in diagram does not stop the undo operations.

This is a regression issue. 

Expected: 
UndoBufferSize 0 means no undo possible.  
RedoBufferSize 0 means no redo possible.

Worakround if applicable: Set the UndoBufferSize to 0 after InitializeComponent. (this is if you don't need undo/redo at all).