Add-ons Manager in Firefox lets you view installed extensions, plugins  and themes and allows to disable or remove them. Add-ons manager does wastes lot of space, it’s ok – when you’ve few extensions installed,  but if you’ve lot of extensions installed then that space can become precious where you need to scroll down to the bottom to access an add-on, where Cleanest Addon Manager  Firefox add-on removes this wasted space without compromising any functionality and makes your add-ons manager look cleaner than before.

cleanest Addon Manager

Install Cleanest Addon  Manager for Firefox