SetMinimumSize() does not work for me. I think it is because I change the window's position. However, the problem was in my form file. For an unknown reason, it changed the window's size to 802x600 when I was checking for 800x600. Maybe there was some another way out, but now all works just fine.

Hi,

An educated guess is that the second case is handled by the window manager (the decoration is not done by Qt).

One possible thing to do would be to check the screen resolution in your method and try to adapt to that.

Hi and welcome

Maybe
void QDrag::setPixmap(const QPixmap & pixmap)
Could be used ?
You set it when you start the drag so it sounds it might do what you want.

@eLim You're Welcome :)