game does not register mouse clicks

So I downloaded the minecraft.dmg file and ran it. It downloaded all the updates, the game launched normally. Then, when I tried clicking "Singleplayer" or any other button - it doesn't respond.

What I've learned about the error:
1) MC doesn't respond to mouse clicks
2) Occasionally if I move my mouse over a button the button would light up, as if the mouse was over it. Even if my mouse is not above it. Then clicking anywhere would trigger the lit button (even if the mouse is above another button)