If a resize of a widget is done from the top-left of the window the pos() of the window will no longer be correct. It is not updated to reflect that the position of the window has changed. This affects both pos() and geometry().

There is however a workaround, thus it is possible for the window to know its size.

To get the position correctly:

QPoint global = widget->mapToGlobal( QPoint(0,0) );
global += (widget->pos() - widget->geometry().topLeft());