You can move your cursor on a game mode in the game mode switcher without highlighting that game mode

To reproduce:

1. Bring up the game mode switcher by holding F3 and pressing F4
2. Keep holding F3 and move your cursor to some game mode
3. Press F4 to highlight a different game mode
4. Move your cursor ever so slightly and observe the highlighted game mode not change

May require a few attempts to reproduce. Easier to reproduce in larger windows/fullscreen.