The typical Linux GUI uses a pointing device with three buttons; the 
center button can be emulated on two button pointing devices by 
simultaneously
depressing both buttons.  (Some track balls only have two buttons plus a 
scroll wheel -- depressing the wheel is the center "button".)

What happens with a laptop that has only a touchpad but no buttons? 
"Tapping" on the touchpad performs the MS Win 10 "button" functions, but 
what about
Linux use?  Can one configure the touchpad so that a specific set of 
regions work only for "tapping" and thus emulate a button, and the rest 
works as a regular
"glide" pointing device?

If not, is the only mechanism to use such a machine, without pointing 
device physical buttons, is to have an external (e.g., USB attached) 
mouse or trackball with buttons?

Also, are there packages to enable in Linux GUIs, and compatible with 
EL7,  touchscreen devices?  If so, does anyone have direct experience 
with the actual functionality
provided by such Linux packages -- are these end-user usable?

Yasha Karant