Fix button colors when loading

[dorianvp]

Buttons currently turn gray after being pressed (and while executing some sort of process). This can be seen especially in the start screen.

[juanky201271]

Right after you press a button turns disable, to prevent the user can click several times on it... well, if this is so disturbing we can think in some different approach... a real disable look & a fake disable look for right after it pressed...