I'm not 100% sure how to fix it, but if you're teaching class, do not interact with the students. When you get back to the lesson afterward, the "Finish the Lesson" tab disappears, leaving you stuck on that screen until you load a previous save. Figured it out. The "Finish the lesson" tab was included in the "if previouspassage is slumschoolclass" statement. When you interact with a student, the previous passage is no longer slumschoolclass, causing "Finish the lesson" to disappear. Moving the closing "/if" above "Finish the lesson" fixes this. Note that this is a bootleg way of fixing it that also causes "Finish the lesson" to appear when reading a book in the library. Better than being trapped in class though
Clicking on "Finish the lesson" causes the browser to spit out an error. This is because "set schoollearning" isn't properly closed. It only has one ">" instead of two
School projects will be completed twice as fast as intended because "schoolprojecttimer" is taken from twice in the same hourpassevents cycle