when you edit CSS, SCSS, or Skin cards, the site's actual css (which comes from file cards plussed to style rules) are not regenerated.
actually, they are immediately updated now. However, you have to do a hard reload to get the new skin unless you update the *style rule directly.
(still, I think prompting is ultimately the better way to go)
..or we could go the other way and prompt for some sort of preview....
Now the reloading is immediate. But special preview support would be great...
prompt for immediate update when editing skin-related cards+discussed in support tickets
prompt for immediate update when editing skin-related cards+relevant user stories