Here's the deal.
I converted one of our forums, forum.technightowl.com, from vB4 to XenForo. I have more or less carried over some of the styling options from that forum to this one, but made 99% of the changes under styles. There are two or three template changes, most significantly for the header meta tags and the copyright notices in the footer.
I have also placed three sets of banner ads on the forum, and added maybe a dozen or so add-ons that impact board messages, global feeds, and some other odds and ends.
So here's the problem:
With Safari on a recent iMac running 10.7.1, when I leave the forum home page open and switch to another tab, after a few minutes, the page turns black, except for the banners. Note that these are the same banners that ran under the vB forum. A fast refresh fixes it. I cannot duplicate the problem in the latest releases of Firefox, Chrome, or Opera.
I have NOT seen this phenomenon on any other XenForo forum, just mine. I'd like some guidance as to what's going on and what, other than removing the banner blocks (we get paid for them so that's not an option).
This is also important to me in another way. I have two more forums, one with nearly 120,000 messages, that I'd like to move over after your 1.1 version ships, but they will also be similarly styled, so we need to address this problem first.