Can you try the online help with the browser console enabled (F12). If you click the dropdown, do any errors show in the Console tab?
No, no errors show in the console.
This is grasping at straws and a real long shot, but is this an upgraded project?
If so, does anything change if you click Tools > Update DHTML Effects in Topics then recompile?
It is upgraded - from RH8 or 9, if I remember correctly. I'll check out your recompile suggestion in a day or two when I have time to get back to it. Thanks for the help.