I actually went to the trouble of taking a screen grab of it and counting the pixels and it's only 15 pixels high! I mean come on!!!
What I really want is something at least half the size of the foreground/background colour picker. I like to use the colour picker as a kind of painters' palette, so it's good to roam around and be able to get the shade I want. But then again I'm a Maya guy and am used to being able to change the interface of the application to how I want it.