I couldn't find an explanation or other bug report so: In Firefox 3.0 it was possible to "double-click" a tab which enabled the control and then one was able to navigate through the tabs by using the arrow keys on the keyboard (left/right). This doesn't work anymore with FF 3.5b4.

Bug 491178 - Its not possible anymore to change from tab to tab with the arrow keys!

(In reply to comment #1) > Bug 491178 - Its not possible anymore to change from tab to tab with the arrow > keys! It's not true : hit Ctrl+K, then hit Tab - you still can use arrows to change from tab to tab & all other (very useful!) functionality. What's true - it's not possible to focus tab with a click anymore. While I use tricks to get back tab focus with keyboard shortcut now, I still think it's really dumb & even rude to kill this feature totally. Clicking tab with 'modificator key' pressed to gain focus would work for us geeks who were supportive & loyal to Mozilla for years.