Most code editors have a TODO list if you comment something that starts with TODO for example. The IDE then bundles all TODO comments and adds them to a list, so you can see them everywhere. This can be useful as reminders if you added something but know it can be improved, or you had to quick and dirty add something for a demo which has to be fixed properly at a later date, or just as a reminder to ask a coworker when you see them.
It would be great if Mendix would add a similar TODO functionality to studio pro, where you can add TODO items so you have a reminder to look at something at a later point.
Nice idea and a big miss from Mendix!