Hi,
CallCommand() is exactly the same as a user choosing a command from the menu or clicking a palette button. So, indeed using CallCommand() most likely involves the creation of an undo step, and there no means to avoid. So, as soon as your code creates additional custom undo steps or makes use of CallCommand() multiple times, multiple undo steps are inevitable.
The only workaround would be to do the work done in a command manually. For certain commands it may be easily achievable as the API provides functions toi achieve the same directly, for other (and unfortunately most) commands it will involve more work, up to the point of re-engineering the internals of one of our commands.
Cheers,
Andreas
