void gdk_window_unmaximize ( GdkWindow* window )
Unmaximizes the window. If the window wasn’t maximized, then this function does nothing.
On X11, asks the window manager to unmaximize
window, if the
window manager supports this operation. Not all window managers
support this, and some deliberately ignore it or don’t have a
concept of “maximized”; so you can’t rely on the unmaximization
actually happening. But it will happen with most standard window
managers, and GDK makes a best effort to get it to happen.
On Windows, reliably unmaximizes the window.