It might take some time to get used to the new Firefox theme as it changes the display of the tabs quite a bit to gain as much screen estate as possible. The theme is also changing many of the icons including those in the navigation toolbar of the web browser but also scrollbars and other elements.

New themes do not always support all Firefox extensions. The software developer has taken extra care by ensuring that the Firefox theme is compatible with dozens of popular add-ons. The Littlefox theme is ideal for users who want to save screen estate. Might be ideal to run on a netbook where vertical screen space is limited. The downside is that the theme is not visually stunning at all but that is also not the purpose of it.

Some of the changes can also be achieved in other ways. You could check out our Setup Firefox To Use Minimal Screen Estate for some pointers on how to do that.