When on the Koha main staff client page if you click on the ? in the top right to get the help file it only loads sometimes.
If you're at http://my-koha-site.com it doesn't work. If you're at http://my-koha-site.com/cgi-bin/koha/mainpage.pl it does work.
This bug is older, but 8705 has a patch so I guess it wins!
*** This bug has been marked as a duplicate of bug 8705 ***