Unfotunetelly I has to say, that there are some very urgent things which I has to do.
So I can't try out your proposal in the next few days.
But I thought a little bit about your post:
- When I install an eventfilter, I think I must not check where my mouse is.
I think QWT / QT handles it in the correct way.
Because I already installed an eventFilter in the canvas and it works without checking the mouse coordinates.

Is my assumption correct?

Thank you in advance