Those scroll bars are lacking in FireFox under Mac OS 10.6.8, but I worked out that I can scroll using the up-arrow and down-arrow keys.
I have a more serious problem using the discussion forum on my iPad: the "quote", "edit", and "flag" links are mouse over text, so I can't see where they are unless I tap on them: which is treated as a click. Usability is low.
A "cancel comment" option is needed beside "post comment" under the comment input window.