Select this checkbox to allow a student to add a course they have previously taken.
If this checkbox is cleared (not selected), a student is unable to add a course they previously have taken.
Suppose you have scheduled 3 sections of the same catalog record in the same term. Note the begin and end dates of these classes. The end date of CIS 1151 01 is less than the begin date of CIS 1151 02, and the dates of CIS 1151 03 span the whole term and thus overlap the dates for CIS 1151 and CIS 1151 02.