Why Tk treat F10, F11, F12 diferently from F1...F9?

[Gabriel B.]

This is completely odd to me...

# Bind F1...F12 to <<TabKeys>>
self.tk.event_add( '<<TabKeys>>', # keys used to switch between the tabs
'<KeyPress-F1>','<KeyPress-F2>','<KeyPress-F3>','<KeyPress-F4>','<KeyPress-F5>',
'<KeyPress-F6>','<KeyPress-F7>','<KeyPress-F8>','<KeyPress-F9>','<KeyPress-F10>',
'<KeyPress-F11>','<KeyPress-F12>'
)

self.master.bind_all('<<TabKeys>>', self.__functionKeysPressed )

def __functionKeysPressed(self, event):
print event.keysym
Now, i run the program and press from F1 to F12, and i get:
F1
F2
F3
F4
F5
F6
F7
F8
F9
L1
L2
F10 simply does nothing!
F11 prints L1
F12 prints L2

The only place google takes is not very elucidating :)
http://64.233.161.104/search?q=cache...+L1%7CL2&hl=fr

Anyone has any ideia why is that?
I surely didn't mind about this if it wasn't for F10 showing nothing.
I get the return code just to use the same function (and same biding)
for the 12 buttons since i can't pass arguments to the Command option
in tk. ...And i'm already considering adding a L1 and L2 check instead
of F11 and F12 and a 'empty' check for the F10... But that would be
plain ugly.

Thanks,
Gabriel