https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/1026046
Switching our the xserver-input-synaptics (1.7.x) for xserver-input-mtrack 0.3.0 led to the following,
Thumb detection on lower pad - increase BottomEdge
(now a feature of synaptics 1.8.x)
Seemingly random right-click trigger while doing something else, like multi-line selection - reconfigure ClickFinger1
More tweaks may follow.
http://osdir.com/ml/fedora-devel-list/2009-03/msg02131.html
Re-enables the removed functionality permitting those "in the know" how to kill their xserver whenever they wanted to with Ctrl-Alt-Backspace.