I enabled that flag & restarted, but I am not seeing a calibration option anywhere is display settings, or anywhere in settings. Acer spin 713 and Acer 23.8" external monitor. If I mirror then both displays work with touch, but the external is just a bit off. If I extend, or set the external to primary, then touch only works on the chromebook.Alright, it took a bit but I figured it out! there is a feature flag you can enable to fix this. Open chrome and go to chrome:flags This will open the experimental feature flag. Search for "calibration" and enable the touchscreen calibration option. Then go to display settings and calibrate your external touch monitors! works great now.