Attachment that is inside a skin placeholder cannot be dragged outside that placeholder on to slot.

Why?

Hello, thank you for notifying us! We confirm we could reproduce the problem.
I created an issue here: https://github.com/EsotericSoftware/spine-editor/issues/607

I think the problem is related
https://drive.google.com/open?id=12C-40r8aFCtBmQPl0rAtai87rhCwoIEL&authuser=warmanw%40gmail.com&usp=drive_fs

Did you mean to reply on the other topic with this?
[Question]Duplicate a skin with Rename Attachments

oh sorry yes