Bottom outline is missing in the Controls screen buttons

In the Controls screen, all the key and reset buttons doesn't have the bottom outline. In the first screenshot, there's a closer look in the buttons, and in the second, there's a brighter background for better highlight.

I don't know if it's a valid "bug" or not - this is a minor thing, but I reported it just because all the other buttons have complete outline, and it looks kind of weird.