I have a live site that I just noticed isn't displaying the site toolbar in IE 9 and 8 (haven't looked at others). Still displays fine in Firefox, Chrome, and Safari.

What's odd is that the markup is missing, so I suspect that there is some sort of Javascript conflict (I'm assuming the markup is injected using Javascript). However, I tried activating a stock theme from the marketplace and the toolbar was still missing.

I was hoping someone might be able to give me a pointer on where to direct my investigations. Any ideas?