Awesome, Firefox 4 is out! But please to god explain how things like this get past quality control. Firefox 3.6 is first, then Firefox 4.0:

Firefox 3.6 open in tab Firefox 4.0 open in tab

I don't know about you, but I have muscle memory, and I have opened at least 10 links in windows today instead of tabs because of this change. And yes, I would normally just middle-click but this is on a laptop touchpad with no middle button, so I have always gone to the menu.

I should probably file a bug for this (edit: bug filed), but who knows if it is a big enough deal for anyone to care about...