User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 If we have only one tab open, then there is no "x" mark for that tab, u need to open a new tab, then it shows "x" mark, so then you can close it. In the last version, if there is only one tab open, there used to be "x" mark, and if u click it, it closes the web page and a new blank tab will come up. Its useful when you want to close a tab ( the only tab you are using at that time). In this version, either you need to close the whole Firefox, or open a new tab, then close the previously open tab. Reproducible: Always Steps to Reproduce: 1. Open Firefox with just one tab 2. You do not have "x" mark to close it. 3. It surprises me. Actual Results: You do not have "x" mark to close it. Expected Results: There should be "x" mark on tab, even if have only one tab open.

Dupe of bug 501592, bug 456405.