When I delete one of the options in the drop-down list of a Custom Field, I have observed that while the deleted option no longer appears in the list on new forms and cannot be selected, any existing entries that already had the deleted option selected retain the setting.
Is this behavior guaranteed? That is, it is guaranteed that if I delete an option from my Custom Field list, is it guaranteed that any existing items that use that option will retain it? Is it also guaranteed that if I later add the same option back into my Custom Field list, the option will not be re-instantiated but will instead be indistinguishable from entries that had the same option before it was deleted and added back?
For example, say I have a Custom Field for Billable Time called Category. Say that Custom Field is of the Drop-down list type. Say I have three options on the drop-down list: Apple, Banana, and Cucumber. Now say I create three Billable Time items, one with each Category selected. Then say I go back into Settings and delete Apple from the list. When I look at the Billable Time entry that previously had Category = Apple, it still has Apple. If I leave it alone, it keeps Apple, but once I change it to Banana or Cucumber and save it, I cannot change it back. I also cannot select Apple for a new Billable Time item unless I first add Apple back into my drop-down list in Settings. If I do add it back in, it’s the same Apple as before, and any new Apples I create are indistinguishable from old Apples that were already there. Can I rely on this?