When you select a microsoft intellimouse (wheelmouse) either ps/2 or serial
the installer checks (activates) the emulate 3 buttons option.
This should default to off since an intellimouse has 3 buttons.
The same goes for a mousesystems mouse.
Note that this was already reported in bug: 8448, I'm not reopening this
bug, since another bug reported in the same bug entry is fixed.
This issue has been added to a features request list for later releases.
*** This bug has been marked as a duplicate of 8448 ***