when in X11: how to disable switching tty with Ctrl-Fn and Alt-Fn

Question

It's super annoying that when I'm in X11 session Ctrl-F[1-12] and Alt-F[1-12] switches Linux virtual tty. How to disable it? (Ctrl-Alt-F[1-12] should work).

I'm using startx to start X11 session with i3wm (I don't know if it matters, but AFAIR when I was using display manager and KDE there was no such problem).

Answer 1

In a terminal (within X11 is ok): sudo kbd_mode -s

(see also: question at askubuntu.com)

For me, that solved the problem.