Just when I was beginning to think my FireFox popup blocker was broken, Pete Bevin pointed out that some clever sites are getting around the Firefox default settings by launching popups from Flash. The good news is you can hack FireFox to prevent these new-fangled popups. To do this:

Fortunately, you can get around it:

  1. Type about:config in the Firefox location bar.
  2. Right-click on the page and select 'New' and then 'Integer'.
  3. Name this new setting privacy.popups.disable_from_plugins
  4. Set the value of this new setting to '2'.

Original article at petebevin.com