Arma2 and ArmaOA Menu flickering and lags SOLUTION

[Jerdan]

I had the problem of constant menu flickering and like every 2 sec graphic lags.
My solution was: DISABLE the second monitor and run it only on one!
I was wondering about the lags b/c my system totally meets the requirements.
So I figured out disabling the second screen could help. - Fallout 4 had a similar problem sometimes, so I had to disable my TV aswell (which is my second screen) and it helped.