Current "new" grid layout KCMs do not delete themes immediately. After clicking the delete button, you also have to click "Apply" and "then" the theme deletes. Ideally, this should be immediate.
Cursor themes? Icon themes? Plasma themes?
Window Style themes
>Ideally, this should be immediate. Heh, it's copying the wallpaper which has this (IMHO overcomplicated) delayed delete to allow an undo. We should be consistent.
If we want to allow an undo, we should just present an InlineMessage with an undo button.
This is actually provided by the KCMs themselves and is not a common behavior. I guess we can re-purpose the bug to track implementing one.