Note: Thinking of moving to Ubuntu mate and playing with the live session right now.
My setup insists of a laptop and a monitor connected via HDMI.
However when I close my laptop lid, my laptop display does not get auto-disabled.
The "blank" feature in the power settings is not that useful either. As it tries to blank both monitors and in addition to that none of the display windows from the laptop monitor move to the external display.
I know this is not some kind of buggy driver issue. Since it works on KDE in my experience.
More visual explanation:
What should happen on lid close
