What was just a rumor a few days ago now it is confirmed by one of the Mozilla engineers, the next version of Firefox will have a new extensions manager, with a new design and new features.
First, we need to say that the new extension manager from Firefox will be a some sort of bank of all external applications, I mean those tools that are not part of the browser. And they are: addons, spell checkers, search engines, themes and plugins ( flash, java, etc ).
The new extensions manager will not open a new window. It will be a regular TAB, inside the main window.
Mozilla is planning to use this model in other cases too. For example, in a future version there will be a so called Content Tab. This will group some internal features which currently open in new windows. Bookmarks an downloads manager are two of the features that are going to be part of the new Content tab.
These being said, a lot of users can’t wait to see the new major Firefox Version. And this is because that new Firefox version will also have a new interface.