Investigate warning messages detected on Zync, during osc start-up

[Dan Nechita]

Critical messages:
osc:19800): Gdk-CRITICAL **: gdk_window_move_resize_internal: assertion 'GDK_IS_WINDOW (window)' failed
(osc:19800): Gdk-CRITICAL **: _gdk_pixmap_new: assertion '(drawable != NULL) || (depth != -1)' failed