Possible bug: FF dumps my session if I try to open an external link without closing print preview view. I had left the Print Preview screen open in FF after printing a web page, and I clicked a web link in another application, which would have normally opened in a new tab in FF. However, only the Print Preview window was displayed and when I clicked "Close", the FF window when all white. Back/backspace wouldn't work and I had to close FF and start a new session. I tested this a few times and it happens every time. I didn't think to test whether this happens in Safe Mode.