Theme designer, randomise single colour not updating ui preview

[Adillwma]

When using the integrated theme designer, selecting the randomise color on a single colour choice will sucsessfully update the color on the color picker tiles but the ui will not update to reflect the change, howver it does behave as expected when changing the colour using the click and picker method and also using the randomise all button. Check the single randomise for the missing code to update the ui preview.