We have an implementation with a bunch of users, and a bunch of namespaces, both of which are added and removed frequently, and the users have restrictive perms in the namespaces (lets just say, not %All)... and the users are utilizing the VSCODE extension for development.
Per the instructions and the user experience, we need to run:
GRANT EXECUTE ON %Library.RoutineMgr_StudioOpenDialog TO ${user}
For ... each Namespace, and additionally %SYS for Web Apps.