Why DNS entries removed via "system-config-network" are not getting removed from 'ifcfg-ethX' file ?

Issue

• DNS entries are getting added and well as getting changed via system-config-network but not getting removed.
• When trying to remove DNS entries for a particular interface via system-config-network , the entries are not getting removed.
• To remove the DNS entries, have to edit respective interface configuration file: /etc/sysconfig/network-srcipts/ifcfg-ethX and have to remove DNSx entry from there.