Problem with QScrollArea updating from 4.0.1 to 4.1.0

[SkripT]

Hi all. I downloaded the last version of Qt (4.1.0) for Windows. I'm using windows XP. Before, I was using 4.0.1 version, so I thought that wouldn't exist problems updating my program to the new version. But I'm really worried, because the scroll area that I was using don't works and with version 4.0.1 worked perfectly. Well,this is what I do in the program: I have subclassed QScrollArea and I have reimplemented the method paintEvent to resize the widget that contains the scroll area since the size of the viewport and the size of the image that I draw on the widget. With version 4.0.1 the paintEvent method was called everytime the size of the main window changes, so the widget of the scroll area was ever updated. But my surpise comes when, with the new version, the paintEvent method is not called if I resize the main window. Very strange and annoying. Moreover if I call viewport() method in the paintEvent to know the size of the viewport, it give me invalid values. I have readed the list of changes of the new version but I havent' found anything changed in QScrollArea Could the problem come because I have subclased too the paintEvent method of the widget that contains the scrollarea? I repeat that the same code worked perfectly with the version before (4.0.1). But I have to use the new version because it has fixed some bugs that I need; for example saving jpegs in different quality factors and others. Anyone could explain me why it doesn't work now or what's the difference between the old QScrolArea and the new? Many thanks.