In the properties box for both folders and categories, it would be useful in certain situations to see the ID number of the selected folder or category.
The ID is considered internal, oblique and volatile. I don't show them for these reasons. The ids may change over time, e.g. during a compact/reorganization of a database, certain folder operations etc.
For files, you can use the File.OID variable, which is available for debugging purposes.
If you need the folder or category id for app purposes, you can always get them via the corresponding endpoints. The ids are then correct, for that session.
Ok thanks Mario. I didn't realize that about IDs.
I'm currently getting whatever folder or category ID I need by using an app. I was thinking it would be handy to see it listed in the property box for categories and folders.