Hi Team,

We at Siemens have issues with QMainWindow showmaximize function.

Maximize option for the QMainWindow is not considering the correct screen geometry when Qt::FramelessWindowHint is set, maximized window size is bigger than the availableGeometry()

The problem arises when using the Qt::FramelessWindowHint window flag while customizing the QMainWindow . This customization creates a custom title bar with maximize, minimize, and close buttons on the frameless window. These buttons are connected to Qt slots and ultimately call the showMaximized() function of QWidget.

In a normal application (with the default window flags), calling showMaximized() works fine. However, in our case, using Qt::FramelessWindowHint causes showMaximized() to not function properly.

Refer the attached video(Qt_maximize_issue.mp4) for the detailed explanation of the issue and also the demo applications to reproduce the issue.