Comment 3 for bug 660142

When I run xev, trackpad button presses are labeled "button 1":

ButtonPress event, serial 29, synthetic NO, window 0x2600001,
    root 0x100, subw 0x0, time 42159345, (5,119), root:(666,139),
    state 0x0, button 1, same_screen YES

ButtonRelease event, serial 29, synthetic NO, window 0x2600001,
    root 0x100, subw 0x0, time 42159389, (5,119), root:(666,139),
    state 0x100, button 1, same_screen YES

Similarly, when I have a USB 3-button mouse attached, right clicks are labeled "button 3" and middle clicks are "button 2." The USB 3 button mouse appears to work properly. I get a context menu with a right click and middle click pastes the last highlight.

But when I put "button 3" in .Xmodmap to assign it to keycode 96, I get an error in .xsession-errors. If I use Pointer_Button3 in .Xmodmap, I don't get an error, but those keys don't appear to do anything.