Cannot focus entries on the pack selection screen using the mouse

Unlike the multiplayer screen, clicking on an entry (not its arrow buttons) in the pack selection screen has no effect in regards to selecting an entry.

As a result, players cannot use a combination of the mouse and keyboard to interact with a pack; either the arrow buttons have to be clicked directly or a pack has to be selected with a keyboard to be moved with the keyboard. Players cannot click to select a pack then move that pack using the keyboard.