Asus PB278Q monitor has suddenly decided to go funny

[MrRockliffe]

As above, half of the screen isn't functioning correctly.

See here: http://prntscr.com/5xg7uc

I've no idea what happened - happened after a restart of my computer. Happens on both Displayport and HDMI from 2 different sources.

Any ideas? Bought as a manufacturer refurb with a 3 month warranty, which has since expired.

[DDY]

Is the monitor's OSD menu affected by that weirdness too?

It reminds me of the display "enhancement" side-by-side comparison modes on some displays I've used, perhaps that has turned on somehow?

[MrRockliffe]

Indeed it is. I even reset all the settings (forgetting about my calibrations!).