Firefox 3 address bar drop-down

So I've done a bunch of messing around with Firefox 3 and it's new bookmarks and "awesome" bar, but there is one thing I still can't figure out. What sites are listed in the drop down address bar (before you type anything). These aren't my most recent sites, they aren't my most visited sites?? What chooses which sites are listed in this drop down area and how can I configure what it lists?

 

they are some of your bookmark links (the ones with stars) - sometimes when you don't clear your history - either auto or manually - then these are listed too,

if you want to configure what it lists then you will need to delete some bookmarks