Agree. Crotons are a picky plant. The fact that you are trying to change it instead of answering to what it needs might be an issue. It's a picky plant and wants what it wants like a spoiled 3 year old. They surely don't like change. I moved mine around until it got the sunlight it liked. Then the sun changed during the season and it got too much. It got sad. Moved it again. Then one more time. That was just this summer. Sunlight will change during the season and it seems Crotons are picky about that even though it's gradual and natural. I just keep moving it so that it gets only the kind of dappled sun that it likes. I think I will have to move it yet again. I don't water mine until it needs it about once a week. It struggled for about a year then suddenly it flourished! It looks good now, but soon it will be time to move it again then we'll see! It's Picky!
