Please describe the problem:
The gnome control-center application exits.

Debugging reveals that the problem is happening in gnome-settings-mouse.c.  I
tracked it to a failure from XSetDeviceButtonMapping.  The actual problem is
caused by duplicate button numbers in the map.

After configure_button_layout runs, the map looks like this:
(gdb) p buttons
$25 = (
    guchar *) 0x57fa60
"\001\003\003\004\005\006\a\b\t\n\v\f\r\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037\037als/mous!"

You can see right at the start there are two copies of \003 in the map.
Before configure_button_layout runs, the map looks like this:
(gdb) p buttons
$46 = (
    guchar *) 0x58b170
"\001\003\002\004\005\006\a\b\t\n\v\f\r\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037p\020�X"

This code here in configure_button_layout causes the problem:
      buttons[left_button] = left_button + 1;
      buttons[right_button] = right_button + 1;
left_button is 2, right_button is 0

Steps to reproduce:
1. /usr/libexec/gnome-settings-daemon



Actual results:
The program 'gnome-settings-daemon' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadValue (integer parameter out of range for operation)'.
  (Details: serial 1605 error_code 2 request_code 148 minor_code 29)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
[1143564671,000,xklavier.c:XklStartListen/]     The backend does not require
manual layout management - but it is provided by the application
Program exited with code 01.

Expected results:
A beatiful Gnome environment with themes and fonts and all wonderful things.

Does this happen every time?
Yup.  Unless I comment out my USB mouse driver from xorg.conf

Other information:
Gentoo Linux x86_64, Xorg 7.0, Logitech MX1000 mouse, evdev X driver

Xorg InputDevice section looks like this:
Section "InputDevice"
        Identifier  "MX1000"
        Driver      "evdev"
        Option      "Device" "/dev/input/mx1000"
        Option      "Resolution" "800"
EndSection

(udev rules place the device at /dev/input/mx1000)