Yeah, I’m pretty sure the random part is what you can’t do. I have a bunch of PLE Presets to color Tracks/Events/Parts but they are all to specific colors. As chikitn points out the only option for Colors is to “set to fixed value”
The only potential approach I can think of is to have a bunch Presets to set to specific colors and then to use a Macro to apply them to different Events. Does the color really need to be “random” or is “different” all that’s required? If you had say a series of 10 Colors where each Event got the next Color and then it repeats in the same order, might that work?