I'm not sure if it's a bug or a feature, but I want this to be changed. When a layer mask is selected, the Eyedropper tool doesn't pick up a color sample from the layer - you have to select the layer icon first.
It doesn't matter if it's an Adjustment or a regular pixel layer.
Adobe, do you really think we want to pick up the color from the monochrome B&W mask?!
I've never needed this for ages, but if I did, I'd first Alt+click to view the mask. Don't you think so?
So, make the Eyedropper tool ignore the active layer mask.
Many newbies will breathe a sigh of relief, but now they don't understand why the tool isn't working. As you know, by default the mask on any new adjustment layer is active. This mismatch causes problems.