Right-clicking on the Font Gallery opens a pop-up menu which contains the following options:

Apply   Identical to the Apply Button.

Install  Identical to the Install button.

De-install  Identical to the De-install Button.

Remove Section Identical to the Remove Button.

(Un)Fold Section Folds up or unfolds the current section.

Previous Section Moves to the start of the previous section.

Next Section  Moves to the start of the next section.

Using the pop-up menu can be quicker as it allows you to open the menu and select a font at the same time by right-clicking on the font.