When a name is changed, e.g., change the name in "Persons is a class." to "Person is a class." the old name persists in the content assist concepts list as well as the new name. If the change is made in another, imported file, the old name persists and the new name is not there.
Names appear in the list even if the namespace hasn't been imported.
This is partially resolved with the new mapping strategy. Changes to an imported file are reflected immediately in a file importing the first. However, changes to definitions in the current file are not reflected in content assist concept lists.