> I recently upgraded to firefox 13. > In the preferenced I had set "When firefox starts" to "about:blank" > and "Home Page" to "about:blank". This had worked for several > versions. > > Now -- after visiting a site -- a thumbnail of that site is shown > on the "blank" page now.
Its a new feature of v13. "When opening a new tab, users are now presented with their most visited pages" https://www.mozilla.org/en-US/firefox/13.0/releasenotes/
