Guild Wars 2

So, i’m using MAC beta and play with gamma increased to make it all look brighter. But every time i switch between the game and any other app (like, i don’t know, safari with GW2wiki to save me from inevitable death?..) the gamma drops back to darkness, although the gamma level hasn’t change, numbers the same. When i move the slider, brightness comes back.
Is it my personal bug or what?.. Can it be fixed?

It’s not a personal bug, I am having the exact same issue (also on Mac Beta).

Hopefully you figured this out by now, but it doesn’t matter which way you move the gamma slider, the brightness will increase.