It does not guarantee that if a user edits a frame, he will necessarily be able to save the changes without any problem. At the time he attempts to save the changes, he may be informed that someone else has already saved changes to the same frame. This means his tentative changes cannot be saved, because they would revoke the other user's changes. What KMS does in this case is to temporarily save his changes in a newly created frame, so that he can then map them into the new version of the original frame.
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