另外代號為Gran Paradiso 的Firefox 3還在M9開發中，應該會在近期發行，。有經驗的電腦使用者、網站開發人員和程式設計人員可以下載Firefox 3測試，先行熟悉。
Bug 400406 – Firefox will ignore the “clear” CSS property when used beneath a box that is using the “float” property. There is a temporary workaround JS/CSS code available for web developers with affected layouts.
Bug 400467 – Windows Vista users will get “Java not found” or “Java not working” errors when trying to load Java applets after updating. To fix this, users can right-click the Firefox icon and “Run as administrator”, then browse to a page with a Java applet — doing this once will fix the problem and permanently restore Java functionality.
Bug 396695 – Add-ons are disabled after updating. Users can fix this problem by opening their profile folder and removing three files (extensions.rdf, extensions.ini and extensions.cache)
Bug 400421 – Removing a single area element from an image map will cause the entire map to disappear. There is no workaround available at Bug 400735 – Some Windows users may experience crashes at startup. There is no workaround available at this time.