was one of several readers to point out the release of Firefox 3.1 Beta 2
." An ancillary addition to Private Browsing is a new addition to the "Clear Recent History" dialog box allowing users selectively to erase the last hour, the last two hours, the last four hours, today's, or all browsing history — previously, the wipe was all or nothing. This beta includes support for "web worker threads
," a developing specification that will let Web-based application developers run background processes to speed up their apps. One feature present in Beta 1 is gone in the new beta: Ctrl-Tab switching. According to the developer, the UI needs more work; the feature probably won't be in the final 3.1.