The "Edit in IDLE" submenu we implemented could be moved from a collection of registry keys into the shell extension, which would also let us detect all Python installations, as right now we only have 3.5 and later (we could even filter out those that are missing IDLE for whatever reason). We'd also be able to fully control launching it, so we could set the working directory properly and any environment variables that may be needed/helpful.

I believe we can also do other tricks like treating Shift+Click differently from a regular click, if that was any value (run in IDLE and leave the interactive session open, perhaps?).