no more popup blocking?

I got the Mozilla 1.3 release this morning for Linux, and started 
getting popups on websites.  No problem, go to edit the 
preferences and make sure that box isn't selected (allow opening 
of unrequested windows), and it isn't there.

No problem - I grab the source tarball, compile it, and still no 
option to block popup windows.

Is this a code change, a change in the preferences engine, or what?

Thanks

Steve