Is your feature request related to a problem? Please describe.
Not possible to choose white and black in color picker.

Describe the solution you'd like
Add black and white in color picker in sketch plugin. Easier for users to pick colors than
typing HEX color values.

Another idea is to add a button that clears all current color values and goes back to default colors.
If a user chooses the wrong color and wants to get the default colors back, I think the user must either clear
some cookie or type hex values.