Hi Steven,
thank you for the proposal.
I think, there are 11 user colors for the reason, that all colors may be shown on the small color palette.

The colors are aranged in 6 columns on both widgets and 5 rows.
In the small color picker, the lower-right corner has an icon to open the big color picker.

That might be the reason, why there is one user color less?

It might be also ok to show the last user color only in the large display.

Thanks for any patches.

Take care,
Harald