I just test the RPi Display installation for the 2,8 Adafruit again and after rebooting, the touch control works fine. Please try using a fresh image and installing the 2,8 Adafruit display in the RPi Display plugin.
It works OK with the RESISTIVE Adafruit touchscreen,
I have a CAPACITIVE Adafruit touchscreen, that does not work!
Which type did you test with?