I encountered the similar problem using WP 3.4.1 and BP 1.5.6 when trying to access MyAccount dropdown menu items in Safari 5.1.7 and Firefox 13.0.1 on Mac OS X 10.7.4. Seems the problem occurs when the menu drops down over the header area – as I too couldn’t scroll lower than Profile on the drop down. I did find that if I stretched my browser window wider in Firefox so that the menu was to the left of the header area completely (ie against the grey background) then the menu worked fine. Same true on Safari too. For info – I did the BP compatibility update using the BuddyPress Template Pack. My site is http://www.hncl.org.uk. I also have problem of all member activity/profile type links redirecting to the homepage – guess that’s another issue.
