Sometimes when I open a new tab from an existing one, Firefox switches to the next tab instead of staying in the tab I am viewing (I have kept the "Switch to new tab immediately" option unchecked). This happens even if the tab after the one I was viewing is not the one I have just opened but another one that was already open. It seems to me that this problem happens more frequently (but not exclusively, as far as I can remember) when logged in to Facebook. It isn't a serious problem, but a fairly annoying one. Has anyone got a clue on what is wrong?