I usually don’t run my browsers in the sandbox, mainly because of the download glitch in IE9. I also don’t see a reason to sandbox them since when I need more security in my browsing, I can switch to Safe Zone. I did however notice the following problem running IE9 in the sandbox.
My home page is Yahoo and I opened IE in the Avast sandbox and tried to read the news items. For every one that contained a video, the video would not work. The box containing it wouldn’t even show up.