As I reported earlier, I was having an odd crash when I was switching into ‘Visual’ mode (or even trying to post new or edit) in the WordPress editor. After some experimenting and a whole lot of browser crashes and restarts I discovered some interesting things.

Well That’s Odd

I was offered another updated to latest nightly build. After I restarted I copied the build id for reference: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1b3pre) Gecko/20081224 Firefox 3/3.0.3pre ID:20081224042714. I noticed something odd earlier about that build ID, I’ll get to this later. The browser still crashed whenever I tried to do a post in Visual mode.

So, the first step was to run Firefox 3.1 with a clean profile and what ya know it did not cause a crash when I went into WordPress. Next I reloaded with my current profile and disabled all my add-ons. Restarted and went to WordPress without a crash. So now comes the fun task of re-enabling a couple extensions at a time to see if I could reproduced the crash. Didn’t take long, the first two to get reactivated were About:Config and AdBlock Plus. I was thinking may be it was the about:config extension so I disabled it, restarted and went into WordPress and Firefox crashed. The only add-on enabled was AdBlock Plus.

Well, that definitely narrows down the culprit. So I went to AdBlock Plus on AMO. AMO shows AdBlock Plus was last updated on December 1st, so I thought may be my install was bad. I uninstalled and reinstalled the add-on and upon trying to post in WordPress, Firefox crashed.

Back to the clean profile. I did a fresh install of AdBlock Plus (with no filters) and this did NOT produce a crash. However upon installing the first set of filters, Easy List, Firefox crashed when the WordPress page tried to load. Removed the Easy List filter and restarted Firefox with the clean profile again and the WordPress page loaded fine. Next I installed the Easy Element filter set, restarted Firefox again and no problems. Okay, so it is the filter set that is causing this issue. Interesting.

So, back on my default profile I deleted the Easy List filter and tried going to  the WordPress editor and Firefox crashed. Well, I wasn’t expecting that! So after restarting Firefox I take a look at my AdBlock Plus configuration and noticed a set of custom filters which turned out to be for Delphi Forums. I rarely go over there anymore anyway so I removed all of those and tried going to the WordPress editor. Again Firefox crashed as if on demand. Well, the time had come to take some drastic measures. First I uninstalled AdBlock Plus again, then I opened up my profile folder and removed the AdBlock Plus folder from within there.

At this point on my default profile there is no trace of AdBlock Plus. Reinstalled AdBlock plus, restarted Firefox and went to the WordPress editor page, no crash. Okay, so far so good. Next step I went in and installed the Easy Element filter set. Went back into WordPress played around in the editor switching between Visual and HTML modes. No crashes. Now for good measures, I even restarted Firefox a couple times. Each time the browser held up when I went into the WordPress editor.

Fake ID?

Now, Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1b3pre) Gecko/20081224 Firefox 3/3.0.3pre ID:20081224042714, seemed odd. The Gecko version (1.9.1b3pre) is correct but something keeps changing my user agent to Firefox 3/3.0.3pre. I confirmed this by going into about:config and doing a filter for ‘useragent’ and noticed the entry general.useragent.extra.firefox was in bold meaning it has been changed. When I reset the value it changed from Firefox 3/3.0.3pre to Shiretoko/3.1b3pre. I had done this earlier too, but something keeps changing the value. Not that big of a deal to go hunting this down. For the record though I am running Shiretoko/3.1b3pre NOT Firefox 3/3.0.3pre.