Not complete as it is lacking the ability to use hex, enter the channels separately and also to remember colors.
It has :
- Large stripes for better selection
- One for hues
- One for a gradient towards gray, varying saturation
- One for a gradient between white and black, varying value
- A large field to preview
- The option to vary the stroke color toward the background color
- A reset to black&white button
It is rather slim, so not really a Color Dialog but a Color Picker Tool.