Hey, thanks for the fast response. Yes, that is almost what I am requesting. more specifically, this is about raster mode, but I suppose this could be used in any mode.
Right now: (Pencil Tool): Press ALT to use the color picker.
Request: (Fill Tool): Press ALT to use the color picker as well Just like with the pencil tool.
To explain why this is useful for pixel artists:
Pixel artists usually work with reduced color sets, and would like to see what happens if a single color is altered. So they pick up a color, change it, and then flood fill all the old pixels in the image with the new color. For that process, you pick colors and fill them a lot.
Thanks so much for your time.