When using only one monitor, if the TLE Small Dome Projector app (the smaller window that is meant to be projected onto an external monitor) is quit, the TLE Small Dome crashes with an error message: The Layered Earth has encountered a problem.
This is a bug in the program that will be fixed in a future update.
Solution: Until the patch is released, while using TLE Small Dome on one monitor, do not quite the projector app. If you want to remove it from your monitor please just minimize the app window (click the yellow button in the corner - not the red one)
Thank you for your patience with this issue.