\label{Course_Toplevel_Seq}
Every course points to one ``top-level'' sequence\index{top-level
sequence}\index{sequence, top-level} file. This sequence is specified
by its URL when the course is first opened.

The sequence used as the ``top-level'' sequence can also be changed
later using the \textbf{Course Environment} in the \textbf{PARM}
screen. The danger in pointing to another sequence file in the middle
of a running course is that homework performance data might be lost.