Every so often, the site stops responding and pops up a warning at the top of the page to do with CSRF.
Up 'til now I've been fixing that by closing the site and reconnecting - inconvenient because I lose my place and have to redo whatever I was up to, grump.
Today I found that pushing the reload icon or whacking 'F5' stops the stupid message coming up ('til the next time) and lets me continue what I was doing.
Talking Dell i5 4-core, Windows 7, FireFox ...