New 'feature' in V5.1. On opening, it changes screen colours to a horrible mess.

The new set of colours appears as soon as I open LO and remains no matter what I do. When I close it, the colours revert to normal. I always suspect myself of doing something stupid but I can’t imagine anything I’ve done to deserve this. Main problem is the Menu bar is all black, making life very difficult. Any clues on what I might have done?

WIN 7. Up to date.

Refer the answer here.