Currently if you have multiple selectors on an element, e.g [align-left] + [some-unique-selector] you cannot delete the previous selectors before you delete the last applied selector. i.e you can't just go and delete [align-left] in this instance.
This is problematic when you have a unique selector because as soon as you delete it that selector and associated styles are gone. (I've even tried copy/pasting the page element to keep the unique style) then deleting all styles on the element and reapplying the unique selector but the styles don't always carry through.