Aha! One of our oldest and most distinguished animators! Glad you are still kickin'. 😉
Dragging things across skeletons is surprisingly complex. On top of that, many users don't do it at all. Those two things combined means it likely has more bugs than any other area of Spine. Please keep your eye out for any weird, especially crashes, keeping in mind what items you dragged across skeletons. We have only a few rare mystery crashes that we can't reproduce and it would be amazing to squash them. I'm pretty sure they have to do with dragging across skeletons.