Quick question, have you installed the Internet Explorer 9 Beta ?
I just tried to reproduce your issue, thinking that it must be something content related but am having the same issue.
In my case I am almost certain its IE9 beta which Im about to remove to test further.
Edit : IE9 beta was the cause of this on my system.. maybe one for FMI to keep an eye on.
BINGO! I'd forgotten that I'd installed it. Glad you thought of it and took the time to post. I owe you.
Your welcome Will.
At least I know of the issue now which is always a great help when supporting my clients.
No doubt this will start cropping more and more as IE9 draws close
Will Bullard and SWS:
Thank you for your posts.
I have notified our Development and Software Quality Assurance (Testing) departments to closely monitor this.