Tab Candy for Firefox isn't even officially out yet, and there's already a Chrome competitor; TabSense presents you with a list of your current browser tabs, divided by window.

It gets points for effort, but at this stage, TabSense definitely feels half-baked. Clicking the name of a tab doesn't actually activate it, but it detaches it from its current group (window). Dragging tabs from group to group does work, though, and it causes the tab to move between windows, which is pretty cool. The extension doesn't pop up a whole bunch of Chrome windows. Instead, you see only one window, and all of the others are hidden. That's nice, too.

There's a quick-search box in the top-right corner, which allows you to search tabs by name, and it does work (it highlights the tab that you're looking for). There are no thumbnails. Also, the groups are temporary and were not saved when I quit Chrome.

The main problem at the moment is with activating tabs; I was unable to actually show the tab that I tried to access. As I said, clicking it didn't work. But still, this alpha-grade extension shows some promise, even if it lacks most of Tab Candy's "wow" factor.