Chink in the Open Source Armor? I discovered something by accident yesterday about Firefox (which I love) that is giving me a little pause around the beauty of open source. Maybe I’m missing something – if I am, please comment. I went to download some new extensions into Firefox, and the Mozilla site said I had to upgrade to the new version of Firefox (1.0.4) in order to access any extensions. Before I did the upgrade on my machine, I upgraded my colleague Lisa’s (I was about to show her what extensions were, so I figured it would be best to make a clean start there with 1.0.4). But once I upgraded her, I discovered that none of the extensions…