X11: how to make an application on top

Question

Situation I am using a matchbox keyboard, which is an X11 based application. When an application is in full screen mode, the Matchbox keyboard cannot be seen because the full screen application is in TOP. So, is there a way to run an X11 based application on all screened applications?

Answer 1

You can look at the source of these GTK features and see how they are implemented for the X11 backend:

gtk_window_set_keep_above()
gtk_window_set_keep_below()
gtk_window_set_transient_for()

I think this is the best way to find out how you can do this, of course, the GTK solution should be portable.