I am struggling using a second monitor with my laptop. I tried the different solutions I found in other topics with no clue.
The output of xrandr is:
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected primary 1920x1080+0+0 0mm x 0mm
1920x1080 77.00*
1920x1200_60.00 (0x2b5) 193.250MHz -HSync +VSync
h: width 1920 start 2056 end 2256 total 2592 skew 0 clock 74.56KHz
v: height 1200 start 1203 end 1209 total 1245 clock 59.88Hz
but this seems to be related to the laptop monitor and not the external one.
In Settings
I can only see Screen Display
and not other displays appear or any identify button.
It's a philips monitor, if that could help.
EDIT
This is what I see in Software and Updates
:
Screenshot