Hi Julian,
Thanks for the reply. Yes, I have used wpaActions for both the toolbar buttons and combo boxes, as per your manual. You can check this out in the test code I emailed you on 5th October (Subject: "Undo-Redo Problem Sample Code"). It works correctly for buttons, but not for the combo boxes. The problem seems to be specifically related to paragraph-level operations, i.e. if I select text and execute an action on that (such as fontface change), undo is possible, but if for example I apply a paragraph style (as per the above code example), the style is applied correctly, but Undo is not possible.
I have spent a lot of time experimenting with many variations, including wpaProcess, wpaExec, CurrPar, CurrParAttr, etc., and nothing makes any difference. I've concluded that I must be missing something, but I've decided to cut my losses in this respect and write my own Undo/Redo engine, which is a better solution anyway for my requirements as it gives me more control over implementation. I was hoping to avoid that, but since it's not working out, I'll just get on with what I should have done to begin with :)
Regards,
Brian