Just a day before the release of Firefox 7, Justin “Fligtar” Scott, product manager for add-ons at Mozilla, touched on the impact of Firefox’s current 6-week release cycle on add-on compatibility. Even as he proudly revealed that the open-source outfit had managed to preserve the compatibility of 99% of all add-ons hosted with it while moving from version 6 to 7, Scott conceded that add-ons not hosted on addons.mozilla.org continue to be a problem. However, as it later turned out, they are not the only problem.
Read more at: Maximum PC | Firefox 7 Bug Casts Invisibility Spell on Some Add-ons