Tal, I took a quick look at the results with the current PR and, as someone who doesn't use IDLE other than to smoke test, It looks fine to me.  The concerns I raised previously about the interaction between changing the state of Options->Line Numbers and multiple windows still stands, though.  Perhaps not previously mentioned, this may be an issue specific to macOS where, per macOS interface guidelines (and as provided by Tk), there is only one instance of a menu bar (at the top of the screen) per app, not a menu bar per app window.  Also, since my original review comments, we have eliminated the use on macOS of Tk versions older than 8.6 so previous concerns are no longer relevant.