Managing Your Fonts
Each time you add a font by hitting the “Add” button, it goes in to your “Fonts in use” repository. You can change the order that they will show up in the user interface by selecting one and using the up and down buttons. To take a font out of your fonts in use, select which ones and click remove, this will put them back in to their respective locations.
As noted in the Google fonts section. When a particular font has a bold or italic option available the respective checkbox will be enabled in the preview box.