I'm continually running into the problem of my child widgets appearing all scrunched together in a little box instead of taking up what I would imagine is the actual screen space. I'm not sure why such small size parameter are being passed down. I don't want to set minimum/maximum sizes as this needs to be adapted to different screens.

My immediate problem is setting a splitterinside a tab. It takes up maybe a quarter of the width. The children of the splitter are thus in a small space instead of taking up the whole tab. I think there is something fundamental to Qt I am missing here. If someone could give me a hint with how to procede it would be greatly appreciated.

I'm using PyQt but its all the similar, here is how I'm specifying the splitter size:
splitter.setGeometry(QRect(0, 25, self.frameSize().width(), self.frameSize().height()))