Mail tags to add/edit (3 state check box)

Hi, i do suggest to use 3 state checkbox to add/edit mail tags. Epsecially when you select several messages and try to manage mail tags . My suggestion to 3 state check box for each tag ( i.e. → 1) new(checked), 2) remove(unchecked), 3) no changes (indeterminate) . all movements with NO IMMEDIATE EFFECT. Two buttons [APPLY] and [DECLINE] or something like this should be add into the form to select.