If I have a menu with too many items to fit on the screen, how do I get one of those 'more' buttons with a downward arrow at the bottom of the menu? Is that supported?
I solved my problem with cascading menus. I already had some, but I didn't want to use more for these particular menus items—but after closer inspection, I think it's better this way.
I'm still interested in other solutions, for scenarios where cascading menus are not a practical option, however (like if the screen is too narrow to cascade that far or something). So, I don't plan to mark this as the accepted answer anytime soon (even though in most circumstances, it's probably the best solution).
Tkinter: How do I handle menus with many items?