What could be changing keymaps behind my back?

[Jorge Santos <jsf@ciencias.unam.mx>]

Something is changing keymaps behind my back, seemingly randomly, from
having:



xmodmap:  up to 2 keys per modifier, (keycodes in parentheses):

shift       Shift_L (0x32),  Shift_R (0x3e)
lock        Caps_Lock (0x42)
control     Control_L (0x25),  Control_R (0x6d)
mod1        Alt_L (0x40),  Alt_R (0x71)
mod2        Num_Lock (0x4d)
mod3      
mod4        Super_L (0x73),  Super_R (0x74)
mod5        Scroll_Lock (0x4e)



I go to:



xmodmap:  up to 3 keys per modifier, (keycodes in parentheses):
 
shift       Shift_L (0x32),  Shift_R (0x3e)
lock        Caps_Lock (0x42)
control     Control_L (0x25),  Control_R (0x6d)
mod1        Alt_L (0x40),  Alt_L (0xe9)
mod2        Mode_switch (0x71),  Mode_switch (0x74)
mod3
mod4        Select (0x73),  Mode_switch (0x74)
mod5        Scroll_Lock (0x4e)


Note how the modifiers get quite changed, Super_L turns into Select,
and Super_R turns into Mode_switch.

This is getting to be quite annoying.

And I hav no idea what is causing this wierd behaviour.  Any ideas
about what it could be doing it or how I can find out?