Describe the bug

Using the bottom shade adjuster while on the darkest shade resets the selected color to white.

• Is this bug a regression in the toolkit? If so, what toolkit version did you last see it work:

Steps to Reproduce

• Can this be reproduced in the Sample App? (Either in a sample as-is or with new XAML pasted in the editor.) If so, please provide custom XAML or steps to reproduce. If not, let us know why it can't be reproduced (e.g. more complex setup, environment, dependencies, etc...)

Steps to reproduce the behavior:

1. Reproduced in the Sample App as-is
2. Using box-shaped spectrum color picker, select any color on the spectrum
3. Lower shade value to darkest shade using either bottom or left shade control
4. Update to lighter shade value using bottom control.
5. Color resets to white.

Expected behavior

Updating to lighter shade using the bottom control maintains the latest used color, instead of reverting to white.

Screenshots