I'm sure we're all aware now that when we see a greyed-out button, it either means that 1) we cannot click it, or 2) its current state is off - or false.
In my application, I have a square, which acts as a button, next to a list item. This button, when clicked, will either mark the selected item as Important or Not Important. When you hover over this "button", a tooltip appears.
My question is, what should the tooltip say?
If the button is greyed out, should it say "Important" or "Not Important"?
A grey button indicates a not important item, while a blue one indicates important.