While the first beta of Firefox 3.6 did not offer the tab-preview for Windows 7 (you know, those little previews when you hover over running programs in your taskbar, which allow switching direct to a certain tab within Firefox), this feature was removed in the third beta. 🙁
Actually, this feature wasn’t really removed but rather just disabled. In order to re-active this feature you have to open the advanced settings (
about:config) and then just enable
If you even want to be able to cycle through the browser tabs using [CTRL]+[Tab] you have to enable
browser.ctrlTab.previews (you might have to create this settig if it does not yet exist) as well.