A while back when I tried to edit a stylesheet in Firebug I got an error that said “Failed to load source for:” followed by the URL of the stylsheet I was trying to edit. After a long while, I finally figured out the problem. Firebug does not follow redirects, so if your stylesheet URL redirects to another URL, you will most likely get that message. This was a huge pain for about a day until I realized that I could “live” edit the stylesheet in the same way with the Web Developer Firefox Add-on. In this case, we had setup a canonical domain redirect that redirected all non www traffic to wwww. The stylesheet was being called from the non www URL, thus Firebug wouldn’t let me edit it. Problem solved!
Firebug Error “Failed to load source for:”
Dec 01, 2010