all level3 or nb3 nbsp options give only level4 nbsp

[Dominique Meeùs]

12.04
keyboard pc105, be, oss

I tried (with gnome-control-center) different options supposed to give non break space on level 3 but if I get some non break space, it is on level 4

For the moment, I read in gconf editor:
/desktop/gnome/peripherals/keyboard/kbd/options : nbsp nbsp:level3

The keyboad display shows nobreakspace on both level 3 and 4 !
I get a non break space only on level 4