gtk_box_pack_start( GTK_BOX( vbox ), button, FALSE, FALSE, 2 ); // insert the button in the box
gtk_window_set_position( GTK_WINDOW( window ), GTK_WIN_POS_CENTER ); // center the window on screen
gtk_box_pack_start( GTK_BOX( vbox ), button, FALSE, FALSE, 2 ); // insert the button in the box
gtk_window_set_position( GTK_WINDOW( window ), GTK_WIN_POS_CENTER ); // center the window on screen