User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0.1) Gecko/20100101 Firefox/9.0.1 Build ID: 20111220165912 Steps to reproduce: I clicked "Open All in Tabs", within a folder of several bookmarks. Actual results: Since one of the more recent versions, it no longer opens them in the current tab. It opens them all in a new tab, leaving the current tab. Expected results: The expected behaviour exhibited in the rest of the browser is that left-clicking a link or bookmark takes the current tab to that page, and middle-clicking a link or bookmark opens a new tab with that page. This is not what happens when clicking that, even though it used to, forcing the user to have to close the useless tab everytime.
That is intentional, caused by bug 440093, and is documented in the release notes of Firefox 8. https://www.mozilla.org/en-US/firefox/8.0/releasenotes/buglist.html