Disabled Buttons: Color Doesn't Change
I've got "back" and "next" buttons on the base layer which are coloured green for all states except for the "disabled" state, which is coloured grey. Clicking these buttons will show several layers in a set order both forward and backward.
The idea is that the "back" button will be disabled when the first layer is visible (since there is nowhere to go back to) and the "next" button will be disabled when the last layer is visible (since there is nowhere to go forward to).
This is working so far except for one puzzling thing: although these buttons are functionally disabled when the first/last layers are showing - they are not displaying their disabled color (grey) - instead they remain green.