Use a select list for the existing course titles, use a recordset to populate the list. and a text box for new course title.
Use an insert record behavior to insert the new course title. For the trigger, click the lightning bolt icon, and select the New Course title text box. This will insert a new record if a new course title is entered, but skip the insert if new course title is left blank.
In the insert record behavior, set the save Inserted ID in Session option to a session named:
after the insert behavior, use the following code to set the CourseTitle form element to use the inserted ID if it exists:
<?php if((isset($_SESSION['NewTitle'])?$_SESSION['NewTitle']:"") != "") $_POST['CourseTitle'] = $_SESSION['NewTitle']; ?>