I'm wondering why I have to explicitly set CSS properties that use calc() with GSAP before being able to Tween to a calculated value? It doesn't matter if the value is set with CSS beforehand, I still have to register it with GSAP before being able to animate it.
// Have to set if first
TweenMax.set(element, { width: "calc(25% - 10px)" });
// Now I can tween it
TweenMax.to(element, 0.5, { width: "calc(100% - 10px)" });