I don't know how this is usually done in fantasy maps of this type, but I'm more familiar with how it is done in real world UK Ordnance Survey maps. They either use little bluff symbols or they use hachures - especially in slightly older maps of the mid 20th century. So your idea of a line isn't too far removed from that. I might add some small hachures to the cliff side of those lines if I were you. I made some just recently for my John Speed map of Dorchester if you want some quickly without having to draw your own. They are available here at the bottom of this blog, and were used in the John Speed map with Symbols Along:

If you find this little group of hachures too cumbersome to handle as a group (there can be issues if you want to go around rather tight corners) you can easily break them up into a set of separate symbols. It's a vector symbol, so it's perfectly editable.

Pretty good for a beginner :)

Just wait until you get into procedural texturing!

Sorry I couldn't be more help than that.

I hope you get it sorted out soon. It's a good looking map.

I think you might have to contact Tech Support about it because I can't replicate it here on my machine.

The drawing tool display is slower than you might expect because several of the tools have more complicated display images sourced from a set of mini maps (other very tiny FCW files contained in the drawing tool folder) to help mappers see what they are about to draw, rather than the raw lines and polygons as they would appear without the native sheet effects. Normally, though, this just causes a blinking green screen in the background when scrolling the tools, and hasn't so far resulted in things vanishing the way they appear to have done for you. At least - not on my screen they haven't.

Thank you.

I don't seem to be having any issues with the map itself. Unless Remy or one of the others can find something it is just possible that there is a problem with the app itself.

You mention attempting to reinstall and/or repair something in the thread above. Have you done that as the Administrator, and have you then also reinstalled the most recent CC3 update at the end of it all?