The problem is that the left-button and right-button are also included in the touch surface. I found out that this question is common, but I didn't find a solution for Windows(8.1) and Elan(touchpad hardware). Only for Synaptics(another touchpad hardware). I have tried to download latest driver from Elan. It doesn't have a disabling option for that issue.
Refer:
xorg: disable touch sensitivity on clickpad button area on Elantech clickpad
Disable the touchpad buttons from scrolling my mouse
http://forum.notebookreview.com/threads/elan-touchpad-any-way-to-disable-certain-area.730285/
Thanks!
