@Override
        public void remove() {
            delegate.remove();
            if (current instanceof String) {
                deleteProperty((String)current, null); // FIXME OF-2430 by not providing the original value, some event handlers may not be able to handle this.
            }
            current = null;
        }
Removes the property corresponding to the current key from
the underlying map. Also applies update to the database.
xmppserver/src/main/java/org/jivesoftware/openfire/group/DefaultGroupPropertyMap.java