Counts only number of tabs of current browser-window.

I would like this if it worked - it's very simple and shows simply one number on icon. For most likely totally useless, but I'd like to see it. But it only shows the number when I'm on "new tab" page - when I go to another page or switch to another tab, the number disappears. I would consider it useful if I could just see how many tabs are open by quick glance, but instead I would need to:
1) open new tab
2) look at tab count
3) close the tab
...
4 (some times): switch back to the tab you were in originally.

So no, not worth it.

very bad. Causes firefox to hang when there are man many tabs opened. Spikes the memory usage as well. Please FIX it.