Perhaps now that twitter has taken away the option to see latest tweets first this needs extension tweaking? Just cleared cookies and had to log in to Twitter and the option is GONE. Looked for a FF extension, found this, but it's not working correctly. I see an *occasional* latest Tweet but mostly top Tweets from hours and days ago.

Edit to add: If I go to an individual's account, it works. I see their Tweets in chronological order, with latest first. On main Twitter it does not work.