Activates and shows the window to the user. If it was hidden, it's shown. If the window has been overlapped by other windows, it will be raised to the top. If it was minimized, it will be unminimized.
The method is useful to show a window which already exists, e.g. when there is a "Show preferences" menu item in your application, but the preferences dialog is already open, but hidden somewhere. In that case you should use this function.
See also: show_all()