A pallete is a very specific thing.
A toolwindow is a generic thing.
Having a histogram up on a display that is not color correct to your existing display is not going to matter that much. Having a color picker or a pallete there can range from mildly annoying to the kind of anger that rivals Mike Tyson in the boxing ring.
This is why we have different words, so you can say what you mean, instead of using a word incorrectly and then making up another word to cover up the fact that you didn't say what you meant.
For web layout, or images with absolutely no anti-aliasing at all, it is permissable to work "by the numbers" using Pantone colors.
For everything else... unless you want to end up biting off the tip of someone's ear, I'd suggest you aquire monitors that represent colors correctly.