I want to add the Room key numbers in the map that only the DM/GM can see. When I attempt to hide the text, it completely disappears and I cannot find it, thus having to Ctrl + Z to undo.
It is currently not possible to hide layers from the players only.
There is a Feature Request for GM layers though.
What I normally do is have a second copy of the map with all the GM keys in place so that I can quickly switch between them when I need to reference a location.
Thank you for letting me know about the Feature Request, and for a work around. Very handy.
// Closing as resolved