Cartographer Bug: Fault Line

I was working with Cartographer today and opened up BoloReich so I could copy and paste. Strangely enough, when I re-opened my map in Cartographer (so the changes made in BoloReich would show) my entire tree line was missing and had instead been replaced by ocean. What had happened is that I had selected the trees and left them selected before I went into BoloReich, and I guess if you do that then the part of your map that's selected goes bye-bye into the ocean.

Long story short: Don't leave stuff in Cartographer selected like that, it's worse for your health than smoking and more irresponsible than giving your kid to some alligators because you're tired of raising it.