I have just come across this question and had a look at your problem - which I expect you have sorted by now. I adjusted the conditional formats so they operate by looking for the value in cell $A$1. And I formatted the text to match the background colour, which makes the contents of cell A1 invisible. Finally, I entered the data validation values directly into the list source (simply "0,1,2,3,4", without the quotes). Tweaked version attached!
