You could check that with regular silent pictures. If I remember well, Canon video settings only get applied when you start recording H.264 (and until you do that, it stays at 720p 30fps or something like that - you tell me).
Currently you can't record RAW at the same time with H.264, but it should be doable.
The redraw issue is probably a bug. You could check if redraw() gets called at the end of NotifyBox_task(). If yes, check if dialog_redraw() gets called in _redraw_do. If that gets called, but does not do the right thing, we are probably asking it to redraw some tiny dialog (not the entire screen). I'm not sure how to fix it in this case (need to experiment, probably need to redraw some dialog below the topmost one).