I don't know if this is a bug or not but I was uploading a video to facebook and while it was uploading I thought I would carry on checking out some other stuff. I right clicked on a link and selected open in background tab and it immediatly started to open it in the window I was already in and as a result I had to start the upload from scratch. I thought I must have clicked the wrong thing or something(although in hindsight I have realised that mistake) and tried it again, the same thing happened and again I had to start the upload again.
Like I said, I don't know if this is a bug, but I thought I would mention it so that you knew and could take the necessary steps.
Facebook requires IE. I emailed their tech support about designing the site to seek browser layout engines rather than browser names but like many, they will prbably waite for the coldest day in hell.