Comment 13 for bug 1162216

I spent some time during the weekend to trace the the problem, and I found what looks like a working solution at least for me. Below some more details.

HARDWARE
My laptop is an Asus Zenbook UX31A with Elantech touchpad.
It used to work fine with 13.10, but after the update to 14.04, I had no way to use the tap at all. The two-finger scrolling didn't work all the time.

TESTS
1. Xinput reported the tap to be properly configured, so I've used "set-prop" to disable and re-enable it, again, no success.
Tpconfig (tpconfig --tapmode=1) wasn't even able to set the tap value properly. The command "mev" didn't report the tap event, while others (two-finger, actual clicks) were recognized.

2. Using a freshly created account, I found that it was working fine with that user, so I did a systematic analysis of all the
I traced the problem to the existence of two different config files for touchpad settings (likely, one of them was created after the update):

   ~/.kde/share/config/ktouchpadenablerrc
   ~/.kde/share/config/touchpadrc

I think they correspond to the two startup services I see (Settings->Startup and Shutdown->Service Manager), namely "KDE Touchpad Enabler daemon" and "Touchpad". I would say the former should be the one to keep, but I'm not sure about it.

WORKING SOLUTION
1. I've removed the two config files and I re-configured the touchpad using the Settings interface and I've restored the tap.

2. Surprisingly, the tap stopped working again when the palm recognition was activated, while everything else worked fine so keep an eye on that too.

As far as I can tell, this restored the full functionality on my system, but palm detection must be disabled.