Yes! I had a bad feeling I was just missing something obvious. Thanks for pointing it out for me
Edit: Spoke too soon. Exactly how do I use an expression?
I choose "Set Colour Filter" and choose "Custom Color", but how can I give it an expression when the fields only accept numbers. Perhaps I misread or simply misunderstood what you meant, but in any case I still don't know how to do this.
Edit 2: Durr I could of sworn that I had tried that, but turns out I didn't! For anyone who doesn't know, you must right click just above the color, where it says "Filter".
Although it did give me an error... something about JazzUpTellTaleButton or something. Not sure.