I suggest cancel button in quick edit mode shall be removed. That cancel button is located first from the left, the similar to post button in normal mode. I do not know how many times I ruined my long edits on SMF and here the same thing :o
Ups. apparently here save on the left :)
But anyway better is without cancel. Normal edit mode is OK without cancel button somehow.
Perhaps we should see if they have made edits and if so use one of those JS alerts "are you sure" ... like when deleting stuff.
The current JS saves the original message such that it can be restored back via cancel, so doing the alert should not be that big a deal.