Comment 11 for bug 164793

Okay, I did what you suggested Teej, but I am using the left-handed version of MX610 (which should not and does not make a difference):

Here's what xev says:

left-button: ButtonPress event, serial 33, synthetic NO, window 0x6200001,
    state 0x10, button 1, same_screen YES

right-button: ButtonPress event, serial 33, synthetic NO, window 0x6200001,
    state 0x10, button 3, same_screen YES

scroll-wheel-press: ButtonPress event, serial 33, synthetic NO, window 0x6200001,
    state 0x10, button 2, same_screen YES

scroll-up: ButtonPress event, serial 33, synthetic NO, window 0x6200001,
    state 0x10, button 4, same_screen YES

scroll-down: ButtonPress event, serial 33, synthetic NO, window 0x6200001,
    state 0x10, button 5, same_screen YES

The buttons for volume+,volume- and mute-toggle don't appear in xev but they *work*

forward: ButtonPress event, serial 33, synthetic NO, window 0x6200001,
    state 0x10, button 9, same_screen YES

backward: ButtonPress event, serial 33, synthetic NO, window 0x6200001,
    state 0x10, button 8, same_screen YES

email-button: (like the volume-buttons) doesnt appear in xev, but it works!

IM-button: does not produce any xev event and is currently the only button not working