Here's how to do it:
[MATH][+][2ND][STAT][CLEAR][GRAPH] (This will also work in the MATRIX, LIST, STAT, DISTR, and DRAW menus)
Pressing [LEFT], [RIGHT], looping through the menu, or leaving the MATH menu entirely will reset it.
If you press [UP], a list of your programs will appear (which can be run directly from the menu).
Hitting enter at different locations on the menu will run commands such as "prgm▶DMS" (which just render syntax errors).
I'm not sure of any other ways to cause the glitch, but I think the main part of it is the fact that you enter another menu while in the Help menu (in this case, the LIST menu).
P.S. [2ND][PRGM][+][2ND][STAT][CLEAR][GRAPH] :D