Coat Applicator (is this a bug?)

I have a coat applicator in my inventory and the 'Use Item' page looks like this: click [List expanded]. Should there be a tab where I can choose the coat colour for a horse? Or do I choose the coat colour after I click 'Give'? Please help as I don't want to use this on a horse only to discover that it is an incorrectly-labelled coat randomiser!

Once you select the horse you want to change it gives you a second dropdown for the colors for that breed. it can't populate the colors until you select the horse because not all breeds have the same colors!