To assign a main window to a X11 multi head display, i am using QDesktopWidget::screen(screen number) as the parent of the main window. It is not possible to set the xy position of the window, because every screen starts with (0, 0). The screen have to be assigned at construction.

Since Qt 5.10 or 5.11 QDesktopWidget::screen() is obsolete. We should use QScreen, but QScreen is only a QObject. A QMainWindow cannot be a child of a QObject. It needs a QWidget.

Question: How to assign a QMainWindow to a X11 multi head display? It would be nice if the answer is part of the documentation.