Add a entry to the application menu

Hi
I've got a little dialog base app without any menus and would like to add an "About" entry to the application menu. By application menu I mean the menu you can find under the mini icon in the title bar in the top left corner of the window.
How do I do that? I would also like to add a separator.

Thanks a lot.

It's the window system menu. Unfortunately you cannot put your own actions there.
Qt doesn't construct the window system menu, the whole title bar is provided by the underlying window manager.
There are only a few hints you can give to customize title bar's appearance.