How did I miss this?

I really like Safari as a web browser. It's fast to startup, seems fast to render web pages, and doesn't seem to have a heavy memory footprint. One of my two biggest compliants, or annoyances, with Safari has been that external programs that have a web link that I click on open a new Safari window instead of a new tab in an existing Safari window. I've asked four people at the Apple Store in San Francisco about this, none of them knew a way to change that (Firefox does it "right"). For whatever reason I was looking in the Safari's preference and I found the option that allows this! Now it's not on the "Tabs" tab, where it should be if you ask me, but on the General tab. I don't ever remember seeing this before so I'm wondering if they added it in the 10.5.1 update to Leopard, anyway, it's there and works as expected! Yeah! However, my dilemma continues though, Firefox 3 beta 1 is out and it has some nice refinements in it, so I'm using both right now.