Variant vs. patient columns
Custom columns are either of the variant or the patient type. Variant columns can be added to genes, while patient columns can only be added to the system-wide patient table. Therefore, managing variant columns is done via the configuration area, while patient columns and the general custom column actions can be reached through the setup area.
However, some column settings are global. For instance, the way a column is represented on the submission forms and the type of data going in to the field, is a system-wide setting and can therefore only be edited by a manager through the custom column default settings.
Therefore, if you seek to edit a column characteristic that you can't seem to be able to edit on the display settings form, make sure you check out the column's default settings also.