I've working with a new little guy as well. He was/is hesitant about cup feeding and clearly has more interest in free ranging bugs. That being said I'm also working through coccidia, so I wanted to stop free ranging bugs all together.
He clearly SAW the bugs in my TK Chameleons Gallery and would occasionally snag one up. But not as interested. I decided to try a very small Tupperware container. Similar results. One here and there, but nothing. I realized then it might be too low and out of reach.
So, finally I decided to move the container very close to where he was spending more of his time and he definitely seems to be warming up to the cup feeder as opposed to the gallery.
Like most things chameleons, im hoping it just takes some patience.