Thanks, the example looks good.
By the way, when I duplicate a tree in hierarchy I found that constraints is not copied even if everything is under the tree. e.g. IK constraints, Path constraints. It would be great if Spine can ask me if I want to copy the constraints. (like they ask me if I want to copy the animation keys) especially when everything needed for the constraint is already available under the tree because that is what a user generally would need to do next (adding back those constraints). Adding back an IK may not take much time, but a path constraint would be a little inconvenient because of the settings and the amount of bone, not to mention those bones sometimes are set to unselectable (so that I can select the path instead of the bones) which further make the work more time consuming.
I also want to know what is the name for mapping a hotkey to Duplicate button? I could not find it.