CyberNotes
Web Browser Wednesday




One of the major reasons Firefox is approaching 400 million downloads is because of how customizable the browser is thanks to extensions. In a way Firefox extensions are bittersweet, because they can provide some unique and useful features, but at the same time they can cause some unwanted problems.

It’s been well over a year since I last took a look at the issues some popular Firefox extensions caused. Most of the extensions listed there caused crashes, memory leaks, and excessive CPU usage. Since then, a Leak Monitor extension has been created to notify users when a certain type of memory leak occurs. This has successfully helped dozens of developers eliminate memory leaks in their extensions.

Unfortunately not all of the problems have not been solved when it comes to the extensions. Some can still cause Firefox to crash, leak memory, or make your CPU usage skyrocket. Today I thought that I would revisit the current status of extensions to see which ones are still causing the problems.

Firefox Memory LeakTo find the extensions that have problems, I turned to the Mozilla Knowledgebase as well as their bug tracker. I was able to uncover more than a dozen extensions that have performance related issues, and I’m assuming you’re using the most recent versions of the extensions as well as the latest version of Firefox. You’re sure to have even more problems if you’re using older versions of Firefox or extensions that are outdated.

Below is the list that I came up with, and along with each extension I mention the issue along with any known fixes.

Note: You may or may not experience the problems mentioned. If you haven’t had a problem with an extension there is no sense in removing it.

  • Adblock
    Issue: Has been known to crash Firefox when trying to use Gmail Chat.
    Fix: None available right now. It’s recommended that the extension be removed if you use Gmail Chat.
  • All-in-One Gestures
    Issue: Can cause Firefox to crash, and conflicts with the inline spellchecker on Linux and OS X.
    Fix: None available right now. It’s recommended that the extension be removed if you’re using Linux or OS X.
  • Fasterfox
    Issue: Can interfere with website access, and problems may continue even if Fasterfox is removed.
    Fix: Reset the defaults or start with a new profile in Firefox. Also make sure that you have prefetching disabled in the extension.
  • Firebug
    Issue: Causes excessive CPU usage
    Fix: Disable Firebug when it’s not being used, or create a separate profile to use it in.
  • ForecastFox
    Issue: Memory leaks due to satellite imagery.
    Fix: It’s recommended that the extension be removed, or you can install an older version without the satellite imagery.
  • Google Browser Sync
    Issue: Causes excessive CPU usage with GIF animations.
    Fix: None available right now. It’s recommended that the extension be removed.
  • Google Web Accelerator
    Issue: Crashes Firefox when closing the browser.
    Fix: None available right now. It’s recommended that the extension be removed.
  • IE Tab
    Issue: Memory leaks
    Fix: It’s recommended that the extension be removed, or you can install IE View Lite as an alternative.
  • Loki
    Issue: Memory leaks
    Fix: None available right now. It’s recommended that the extension be removed.
  • Media Player Connectivity
    Issue: Causes Unresponsive Script Warnings
    Fix: None available right now. It’s recommended that the extension be removed.
  • Mouseless Browsing
    Issue: Causes excessive CPU usage
    Fix: None available right now. It’s recommended that the extension be removed.
  • SessionSaver
    Issue: Memory leaks
    Fix: Use Session Manager instead.
  • Tabbrowser Extensions (TBE)
    Issue: Slows down Firefox, conflicts with other extensions, and can stop Firefox from working.
    Fix: It’s recommended that the extension be removed, or you can install Tab Mix Plus instead.

People running Firefox 3 right now should be careful if using the ForecastFox or FoxClocks extensions. Both of those are known to have memory leaks (ForecastFox report here and FoxClocks report here).

The extensions that I’ve listed above are all currently known to have some sort of problem. The bad news is that not all of the extensions have been as thoroughly tested as the ones mentioned here, and that’s because Mozilla relies on people like you to submit bug reports when you encounter an issue. If you frequently notice memory leaks, try a fresh Firefox profile, and then install the extensions one by one until you find the culprit. The odds are pretty good that the leak will be the result of one of your “more complex” extensions, and so you may want to start with those.

Additional resources from Mozilla include the Reducing Firefox Memory Usage page and the long list of Problematic Extensions.