https://forum.qt.io/topic/20921/maximized-window-goes-up-and-hides-the-qmenubar-while-demaximizing
Maximized window goes up and hides the QMenuBar while demaximizing | Qt Forum
Oct 26, 2012 - I click the middle button in the menu bar right side buttons. The unmaximize, make it resizable. If i do that, the window goes up to pos 0,0 for the Graphics...