Possible bug of Qt on QListWidget?

[SkripT]

Hi all, I use Qt4.1.0 for WindowsXP. In my app I make a thumbnailing of images using a QListwidget. I set the icon size and the grid size. The problem is that after filling the list with the icons, the texts of the items are overlaped. I attach an image of the problem. But if I maximize th window, it causes the list widget to be painted again and this time it elides the text well. I want to know if it's the correct behaviour of the list: the user has to call to repaint everytime it inserts a new item in the list or it's just a "bug" of this version of Qt?

Thanks