It may be just me but it appears that the GM overlay is at least partially transparent. While this is probably fine for a lot of stuff I want to mark up a map with significant locations and I only want to reveal these locations to my players as they discover them.
It seems like the best way to do this is to number the locations on the GM layer and then move these numbers to the tokens layer as my PCs discover the locations.
The problem is that no matter what colour I use these map markings are impossible to see when they're on the GM layer because they seem to be transparent and blend into my background map (which is in grey scale).
Maybe some kind of control of the opacity or saturation on the GM layer is in order?