As a developer, on mac and unity I would like the ability to display both menubars: native and widget.

Large screens of more than 40" are becoming increasingly common. The native Mac and Unity menu is always displayed in the upper right corner. On these screens it would be convenient to also have the menubar available within the QWindow.

A simple solution would be to create a subclass of QMenuBar and override setVisible(). Currently this is not possible because setVisible is not virtual.

This request is to declare as follows:

...
    virtual QSize sizeHint() const override;
    virtual QSize minimumSizeHint() const override;
    virtual int heightForWidth(int) const override;
...
public Q_SLOTS:
    virtual void setVisible(bool visible) override; 

The special treatment of sizeHints could be a responsibility entrusted to developers.

QMenuBarPrivate::updateGeometries() should not return when Q_OS_MAC