Please provide a method where we can open the default Mac Color Picker. It is fine that you provide a limited palette that is easy to use, sure, but this isn't 1981 with CGA graphics limiting us to 16-colors, we should have all of the color options available.
And/or at minimum, you should allow us to customize the palette of colors in your built-it color picker. I have thousands of notes with a color palette that I have used for years, and now I can't easily make new notes with that palette because the colors aren't available.