Student enrollment shows each term for the year, and then has an ADD REQUEST after each term.  If you choose Spring term and put 'Algebra' in the add request field, it shows courses offered during any of the terms for the year with Algebra name.  It seem obvious, but expectation is that since adding to the Spring term, it should only allow you to choose from courses offered in Spring term.  If you choose a course not offered in Spring, then it does give an error when you try to save...but how much simpler and easier to find if it showed only courses offered for the term being updated.