A few days ago I upgraded Firefox to the new 3.6.3 version. When an update is ready, I usually update right away. In some cases I even install a release candidate, pre-release, beta or alpha versions. I also always use the same user profile that I carry with me since before Firefox – since Mozilla M16 (milestone 16) back in 2000. I believe that my profile carries a lot of junk in it since all the version changes and upgrades. I’ve had some problems related to that in the past, but this time it was different.
This time a weird (but seen before a few times) bug happened: after some time Firefox used all 100% time of one of the cores of my CPU. At that time FF was frozen and didn’t respond. After some time (10 second, 30 second, or a minute or more) the program was responsive again. In some cases the 100% CPU lasted until I killed the process and reloaded the program. I’ve read some posts and they all talked about some AV add-ons. I don’t use antivirus software so that couldn’t be it. After some trying I figured out that it was an add-on that was guilty of the bug: it was Dust-Me Selectors that is used for cleaning up the CSS. I disabled it, but it turned out that it wasn’t enough. I had to remove it completely and now the problem is gone.
When the bug was still present I figured out that a browser is so important to my work that I’ve started to think about trying out Opera. Let me mention here that I have only once used another browser as my first browser: it was in the nineties when I used the Mosaic. I’ve had problems with it so I soon replaced it with Netscape 1.0. I am using Netscape / Mozilla / Firefox browsers since.