In current versions of Firefox you hover your mouse over a non-active tab [...] to see (after a small delay) a tooltip containing the web page title.
Uh... what is the point of that? If I am looking for a specific tab then:
- I probably want to switch to the tab that I am looking for, so staying on the current one is not required
- if there are a few tabs from different pages from the same domain the difference might be hard to see on a thumbnail (similar page headings with logos)
- and most importantly: opening the tab is faster than waiting for the delay anyway
This sounds like a "cool" feature that's looking for an actual problem to solve.