The mystery of the disappearing sidebar

Anyone else noticing that the sidebar leaps beneath the content? I had it for a while on Firefox, tweaked my CSS and fixed it. Or so I thought.

Then someone sent an email saying they were experiencing the same thing. Hopefully a browser cache clean out will fix it but it might be an IE quirk.

Ohh and whoever sent me an email about this, apologies but I was a bit hasty with my MailWasher settings and it got deleted… sorry!