Bug#629243: Synaptics touchpad disabled:

[ael <law_ence.dev@ntlworld.com>]

This problem with a partially disabled touchpad - the right button
failing to work is especially problematic - seems to have become
more severe. Restarting X repeatedly is now failing to clear the
problem.

I can see no obvious recent package upgrade that might explain the
problem. But many of the system libraries have recently been upgraded:
perhaps one of those has exposed a previously hidden race condition?

Not sure what debug info might help track this down...