Does anyone know why? Thanks.
I think only mentors and admins can use html (but I'm not sure). There's still several commands available- to see the tags for them, just push the buttons above the text box. If you want to make a table or something you can use LaTex.
Or you might want to go to Control Panel > Edit Options, and scroll to Miscellaneous Options, where you can change the editor you use.
Separate names with a comma.