Eugene mentioned in another post about colorblind users and re-design of screens and buttons. I like that the distance to last button changes to a green background when the distance to last is small, but I have a hard time reading yellow text on a green field. The black buttons have yellow text and when the background changes to green, it would be better if the text changed to black or white. The Accept As button has the same issue. Fortunately, I can avoid this problem by moving distance to last to a white button with black text, but if you're re-designing buttons, it would be best to avoid this color combination.