I just upgraded to Ubuntu 17.10 and I'm not sure how to enable mirrored displays (i.e. all displays show the same thing) since the UI has changed.
Tried following the steps in the official docs which mention a "Mirror" option in "the list of monitor configuration".
I'm unable to find such an option. This is what my Displays config looks like:
I found answer here: How can I mirror one of the screens in a 3-monitor setup?
A quick fix (though not perfect when two displays have different resolution) is: Type
>> xrandr
It'll show you all the displays and possible resolution supported. From this output, and display menu, figure out name of the two displays. For me it was: LVDS-1 (built in) and VGA-1 (display I have attached). Then as suggested in the above link simply use command:
>> xrandr --output LVDS-1 --output VGA-1 --same-as LVDS-1
(you need to change LVDS-1 and VGA-1 appropriately, as mentioned above).
That's it, now two displays are mirrored. cheers
You should have some extra options at the top of the screen , not shown in your screen shot.
See this screenshot which shows the display mode at the top.
You need to select "Join Displays" - circled in red. That should do the trick for you.
