How do i get the old tab switching behavior back?

I installed Firefox 8 today to give it another try after a pretty bad experience of switching from FF 3.6 to FF 4.0. Right now, i've dealt with most of the inconveniences of the switch, but there is one thing i don't get. What happened to the tab navigation behavior? I mean, i used to be able to switch tabs from left to right with Ctrl+Tab and from right to left with Ctrl+Shift+Tab. And it was perfect for me. Now Ctrl+Tab is opening some sort of a preview window, and Ctrl+Shift+Tab opens the All Tabs list. How could i get the previous behavior back? I'm too used to it to change myself simply because somebody came up with a new way that he thought would suit better. Thanks.