color editor disabled for layers

If I create and edit a layer, the Color Editor is disabled (i.e. just gray outlines of the controls, no color wheel, no functionality). All the other controls work as expected, on the masked region of the layer. I know the Color Editor used to work with layers - what happened?

UPDATE - Ok I figured it out - you first have to select a point within the mask, with the Color Editor's selection tool. I've made this same mistake before but forgot about it. The thing is, that selection tool icon looks disabled, too. But it isn't.