It can be cured, have no fear....
.
1) Open up firefox and go to "about
:config" (just type it in the address bar without quotes)
2) You might get a warning that this will void your warranty. Proceed with care.
3) Filter the results by searching for 'insertRelatedAfterCurrent'
4) Now simply click the preference until the value changes from true to false.
Then in Tools, Options, Tabs, tick box for 'when I open a link in a new tab, open it immediately'
This makes it go back to the way you are used to.
It worked on mine....No problems
