I'm sorry for all the noise (meaning my duplicate email), I wasn't receiving my mails back from the list and I thought they hadn't got through some spam filter, so I sent yet another one. I just checked and saw your reply, which by the way I don't fully understand.
My first issue is already solved, as you can see in my last post, but the one with the canvas not being repainted isn't. You said:
I doubt that reimplementing an event loop would be a good solution. Probably Qt allows for passing all incoming events to a subwidget.
Indeed it does, though I think they are actually propagated to parent widgets, which is what the main window is with respect to the status bar. And in what I wrote, as far as I understand it, no event other than a key press is being handled, so there should be no "hijacking". I'll look into it and get back to you when I have a solution.
Miguel de Benito.