From: Adam Williamson <awilliam(a)redhat.com>
Oh, I should also note that, IIRC, the intent is that the driver should
detect if there are no physical buttons and enable tap-to-click in this
case. So touchpads which have no buttons and are only supposed to work
with tap-to-click should be OK.
Where does my notebook's touchpad fall in this continuum? At the bottom
corners of the touch-sensitive area are two "buttons" which click with
tactile feedback, but yet are still part of the touch-sensitive surface.
In other words, the bottom corners can actually be deformed/depressed.
FWIW, I enabled tap-to-click -- did I just answer my own question? --
simply because my wife and I both found the mouse to be moving off target
too often when tried using these "buttons".