Hiya!
I think that Retool currently does a decent job at notifying others about teammates currently editing in the current working version. This has been helpful to avoid writing over teammates work.
However, I'm a tab fiend and often forget that I have an instance of the application open in edit mode in a tab somewhere else. This often leads to the same problem where one Retool instance writes over another.
My proposal is that Retool also shows the user a warning not just for when a teammate has accessed the application in edit mode, but also when the current user has multiple tabs open as well.