Ah, understood. Definitely was nit-picky, and at least Factory Planner's GUI covers most of the screen anyway in its case; I just found it a bit jarring. Thanks!

This occurs with no mods enabled (although I first encountered it using Factory Planner, which uses tick_paused to pause the game when its GUI is open).

What did I do?
Enter map mode and zoom in on radar-covered area far enough to see things Map view of radar at SW corner of player coverage, tick ...

Sorry about that! I looked, but didn't realize the main topic list didn't include posts from the sub-forums.

In the last objective of the Ghost rail planning mini-tutorial, the objective text contains error text about an unknown control sequence instead of presumably the word CONTROL with special styling.