Problems using fonction keys (F1 -> F12)

[Rakotomandimby (R12y) Mihamina]

Hello,
I mostly use mc as file manager for my remote server.
mc works with the function keys.
Unfortunately, for example i I want to quit mc, I have to press F10:
that makes tha terminal to pull down its menu.
How do you advice me to manage it ?
I want to keep the keys for mc.
I'm running the 4.2 version of XFCE (debian testing package from
os-cillation).
-- 
ASPO Infogérance       http://aspo.rktmb.org/activites/infogerance
Unofficial FAQ fcolc   http://faq.fcolc.eu.org/
LUG sur Orléans et alentours.
Tél : 02 38 76 43 65 (France)