[rmb]

I've been a Chromebook user for over a year (Acer Spin 713) with an external touchscreen monitor (DELL P2418HT) in extended desktop mode and have had no issues with touchscreen functions on either the built-in or external monitor.

I have recently added a second external non-touchscreen monitor (SE2417HGX) and run into an unexpected issue. (The new monitor is intended for displaying the other parties/presentations during video calls so touchscreen is unnecessary.)

The problem is that with all three monitors active, the touchscreen functions of the external monitor no longer work correctly. For example, if I try to drag something around on the external touchscreen monitor then the contents of my internal monitor move instead.

If I close the lid on my Chromebook it correcty shuts down the internal display, but if I now try to drag something around on the external touchscreen monitor, it is the contents of my other, non-touchscreen monitor that move!

Has anyone else had a similar issue and found a way to resolve it?
Does anyone know if this is a known bug and whether a fix is being worked on?

(The external touchscreen monitor is connected to the Acer's HDMI port with a seaparate USB-A connection for the touchscreen function. The non-touchscreen monitor is connected via a USB-C to HDMI dongle. The monitors display everything correctly - it is just the associated between touchscreen and monitor that gets messed up. The order of the displays as shown in Settings->Device->Displays is 'Built-in display', 'DELL P2418HT', 'SE2417HGX'.

I've tested it the other way around with the touchscreen monitor in the USB-C to HDMI dongle and the moment I connect the other monitor to the HDMI port the touchscreen capability of the external monitor behaves oddly as described above.

I've even made the external touchscreen monitor the primary display and still get exactly the same behaviour.)

 

[rmb]

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.

@AsherF - thanks for the pointer, but did you get this to work fully? I have turned on the flag, restarted my ChromeBook (so it takes effect) and, with the two external monitors attached - one touchscreen and one not, I calibrated my external touchscreen monitor.

The dots appear towards the corners of my external touchscreen monitor as expected. I tap each one in turn with my finger and when it says it is calibrated I Escape out. However, when I then try to use the touchscreen capability of my external touchscreen monitor the ChromeBook still thinks I am touching the internal touchscreen display.

I do not get the option of calibrating my internal monitor and, whilst it gives me the option to, there is no point in trying to calibrate by external non-touchscreen monitor. So I am still facing the same problem - with both a touchscreen and non-touchscreen external monitor attached to an Acer Spin 713 I am unable to use the touchscreen capabilities of the external monitor. The moment I disonnect the external non-touchscreen monitor then the external touchscreen monitor works just fine.

 

[rmb]

Weird it totally worked for me. As soon as I calibrated the external monitor everything was ok. It also did not give me the option to calibrate the internal screen which is fine. Also I have the external touchscreen set up as the primary monitor. That may help.... and I am on the beta channel for chrome. Try changing those settings and re-calibrating and restarting.

Thank you, your suggestions helped me keep playing with it. After a little more experimentation, it turns out that it doesn't have anything to do with the beta channel or which is the primary display...

When performing the callibration, the last step is to finish the calibration process. The on-screen messages show "Calibration is complete" and "To exit calibration press Esc". Doing the latter does not save the calibration. It all worked perfectly after I touched the tick next to "Calibration is complete" rather than pressing Esc. Perhaps I was being a bit dumb - but the on-screen messages could be more instructive (e.g., "Touch here to save the callibration").

I now have a fully working touchscreen external monitor and internal touchscreen display as well as an external non-touchscreen display: much happier!

Now I need to work out is why, when a window spans more than one display, the only part I can see is the part on the monitor where my mouse left it (this is true for both horizontal and vertical monitor configurations). I may be missing something with the flag "Unified desktop mode".

Also, I need to test a flag that offers window inertia, or using the touchscreen to drag a window from one display or another. Perhaps "ChromeOS drag-drop extensions for WebUI tab strip" will be it.

I have more experimentation to do!

 

[rmb]

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.

In my setup, there is no callibration option for my internal display - but then again, I've never had any problems with it. (Acer Spin 713)
The device settings available for my external touchscreen display with #enable-touchscreen-calibration enabled are shown below.

#enable-touchscreen-calibration