Tints of spot colors when using DeskPack?

[hkellogg]

I stress that my students should understand spot colors when working with Esko's DeskPack. I gave an assignment to create a pizza box with 3 specific colors. When I noticed my student using an additional color I stated that they can simulate the additional color with a tint of one of the three. However, when they used a tint of the spot color, it didn't show up on Studio Designer. Any thoughts why? I checked and they used the tint, not transparency.

Thanks

Hans