Touchpad settings do not affect touchpad on Dell-XPS-12 933

I can not use GUI controls to enable/disable the touchpad on Dell-XPS 933 running 14.04

Turning on/off in "mouse & touchpad" has no effect

Installed touchpad-indicator
Regardless of any settings I choose within touchpad-indicator they do not affect my touchpad. it works when "disabled". scrolling options do not work. still works with mouse plugged in when option is selected. Indicator and pop-up notification say "disabled" but it still functions.

synclient TouchpadOff=1 has no effect

Used xinput -list to find device id

Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ ATML1000:00 03EB:842F id=12 [slave pointer (2)]
⎜ ↳ DLL05E3:01 06CB:2734 id=13 [slave pointer (2)]
⎜ ↳ SynPS/2 Synaptics TouchPad id=15 [slave pointer (2)]

xinput set-prop 15 "Device Enabled" 0 has no effect.
(USING id=13) does disable it though!

How can I get "touchpad-indicator" and "mouse & touchpad" to use the "correct" device ID?