Game rule buttons on "Edit game rules" screen are highlighted despite being covered

The bug

The game rule buttons on the "Edit game rules" screen, shown when creating a world, are highlighted despite being covered by the bottom overlay containing the "Done" and "Cancel" buttons.

See (20w48a) Game rule button highlighted through overlay.mp4

Reproduction steps

1. Open the "Edit game rules" screen
2. Scroll the list so a game rule button is barely visible above the overlay at the bottom of the screen
3. Move the mouse to the top of the "Cancel" button
   The game rule button is highlighted (white outline) despite being covered