Hi Atlas,
thank you so much for helping me out here.
Yes, I did change the background color of the text window to black manually for every marker : (
I did that already in Logic pro 9.
And LogicProX switched everything back to dark grey.
But I would prefer that all the LogicProX frames would be black and that all background colors would be black by default.
And only the marker text bright white by default.
Well, I tried another solution.
I found another application called midi presenter.
You can send out program changes to keynote to switch between keynote slides.
Works fantastic. I use a long LAN cable for midi and have the application and keynote running on a separate Mac mini, which is driving the lyrics monitor.
I think, this is at least the best looking solution for now.
Many thanks again