I just discovered a cool new trick! It's a "Set Color" block trick.
Drag out an object from the Editor.
Pick your "When".
Drag out a "Set Color" block.
Go to the Colors menu.
See that little ? in the top right corner of the Colors menu? Tap it.
You will be in the Values menu. Choose your Value!
You're done! Also, don't forget to set your Value to a number! The colors are all numbered, the Plum Purple one in the top left corner is 0, next one's 1, and so on. Enjoy your coding!