More GUI experiments, I was making some prefabs for generic shapes with ragespline and got a carried away.
Making this actually work as intended was harder than you would think, but I may have just had a hard time because I haven't done it before. I had to use multiple trigger layers that the camera culls out. More than one is necessary for rollouts because you have a trigger area to open the rollout and then another that works as a boundary limit for your mouse to operate in.
Mostly I just took a while to realize that the Mouse Pick Events were detecting everything, so I had to cull that down to my UI triggers layer, but then the triggers were overlapping so I kept getting loops everywhere until i realized that I needed to use separate layer IDs for any triggers that would overlap and then explicitly define the Mouse Pick Events as to which layer they operated on. After that it was pretty smooth.
There were a lot more hierarchy complexities than I expected in order to make it efficient and avoid using too many actions in each state. These rollout UIs could get way cluttered if not properly set up.