void gtk_window_set_wmclass ( GtkWindow* window, const gchar* wmclass_name, const gchar* wmclass_class )
Don’t use this function. It sets the X Window System “class” and
“name” hints for a window. According to the ICCCM, you should
always set these to the same value for all windows in an
application, and GTK+ sets them to that value by default, so calling
this function is sort of pointless. However, you may want to call
gtk_window_set_role() on each window in your application, for the
benefit of the session manager. Setting the role allows the window
manager to restore window positions when loading a saved session.
Please do not use it in newly written code.