Unable to edit costumes that are importing from snap library. Costumes do not appear at all in the editor--blank screen.
Browser: Chrome
Unable to share example, witnessed on several student projects.
Import > Costumes > Ghoul > Edit
What does Snap! currently do?
Currently when you click edit, the editor opens a blank white page. If you draw on it, it does replace the costume when you hit save.
What should Snap! do instead?
The ghoul costume should appear so that it can be edited.
I can reproduce this. Sorry you're having issues with this, the reason seems to be that this costume somehow lost its information that it cannot be edited in Snap's paint/vector editor, because it's a vector graphic with shapes that our editor doesn't support. Instead the "edit rotation point only" editor should open, which only lets you shift the rotation center, but nothing else.
This is a bug in the costume, I'm afraid. I've found some others which also shouldn't open but try to. If you want to edit the rotation center you can do that by either shift-right-clicking on the costume icon, or by right-clicking on the sprite itself onstage and then selecting "pivot".