[MartinH]

Mike,

If there's anything I can do to test/debug the stylus to help figure out the behaviour, let me know. I would probably be able to set up a debugging environment, if needed. My stylus (Renaisser) works differently than the Surface pen, but as far as I can tell it maps to equivalent functionality. Pressing the first button on my stylus is equivalent to using the back of a Surface pen, and pressing the second button is the same as the Surface pen side button (turns taps into right-clicks).

Regarding the feature requests, after understanding more about how the stylus actually works, I can see how it would be difficult to implement an undo button. It seems the buttons themselves don't actually trigger events in Windows (except the eraser button on the Surface pen, which is linked through bluetooth). The fact that a button is pressed is only indicated to windows when the stylus approaches or touches the screen.

So it doesn't seem feasible to trigger an undo on pressing the button, but I think it would be reasonble to trigger an undo every time you tap the screen when the button is held down. It's a bit unconventional, but would be quite functional once you know how to do it.