The current classhelp window uses a frame structure in a new window.

Frames are deprecated.

Consider using the dialog element as demoed in:

  https://www.youtube.com/watch?v=y8HjQETqrOM

as a non-modal with the ability to drag it to allow access to the underlying page.

Opening in a new window with a reference to the original window (so the classhelp can change 
the field on the original form)  is also acceptable. Opening in a new window could be even 
better as the user can choose to open the new window in a new tab if they want.