I always use the right button - 'open in new tab' - I have several windows open at once, keeping the original thread list open until I finish checking thru it. If I post in a thread - it usually opens the thread list at the top of either the BS or other list - depending on what the thread was - Firefox V2 on Win98SE - but my SpeedDial plugin will only open ins a new window, not new tabs - irrespective of what settings I use!