The UNHIDABLE attribute indicates that the element cannot be hidden or shown by the user with the context menu.
UNHIDABLE
By default, a TABLE container allows the user to hide the columns by a right-click on the column header.
Use this attribute to prevent the user from hiding a specific column.
The end user is also denied to show columns that are hidden by default with HIDDEN=USER
Makes sense only for a field that is used for the definition of a column in a TABLE container.
EDIT c01 = item.comment, UNHIDABLE;