Thanks, Andrew, for the offer. I think we have enough to go on right now but we may want to touch base a bit later.

From your comment about how IDLE on macOS is different than it is on Windows or Linux, I assume that means you may be new to IDLE on macOS. Yes, there are a number of sometimes subtle differences. Most of these are differences in how Tk behaves (rather than IDLE itself) and usually with a very good reason: Tk tries very hard to be a "good" citizen in each of the three major windowing environments it is supported: Windows-native, macOS-native, and X11 (Linux and others). As such, Tk tries to look and behave as native applications in each are expected to behave, which leads to subtle but important programming issues, like the fact that macOS applications are expected to have one menu bar that appears at the top of the active display whereas on other platforms, each window may have its own menu bar.  Or Tk uses the macOS-supplied file opening and closing sheets which differ from other platforms, etc etc. That can make using Tk-based apps, like IDLE, more familiar-looking to and easier to learn for macOS users but it can be disconcerting if you are using such an app on multiple platforms. Or perhaps you meant something else.