Rudder

When a rule is in a category that was deleted (but was not empty), then the rule does not show the category anymore, and not the rules.

The rule can still be accessed by direct id, but it can create a mess since people may have applied configuration that they don't know anything about.

In that case, the correct thing to do is to display a category with it's id as name, at root level, with a message ("category was deleted"), et let user migrate and see rules.