Color shown in color window doesn't match color selected

I noticed a  few days ago that when I select a new color using the eye dropper tool, it doesn't match the color shown in the color window. Maybe it's been like this the whole time, but in my memory the window updates when I select a new color. This isn't the end of the world, but I'd love it if I could rectify this somehow. I've attached a screenshot to help explain my situation, does anyone know how I could fix this?

This is kind of a difficult issue to explain so I'm hopefully not repeating a common question!