After loading a new cover to the temporary metadata there is a valid use case to watch also the new full size cover. The user can check whether the just selected cover is correct or not. You cannot judge the size and resolution from the thumbnail and after pressing apply you cannot revert the decision.
I can confirm this bug/missing feature.
After loading a new cover to the temporary metadata there is a valid use case to watch also the new full size cover. The user can check whether the just selected cover is correct or not. You cannot judge the size and resolution from the thumbnail and after pressing apply you cannot revert the decision.