This was reported already in BugTracker..
Highlight what is in your Global VHost Entry and Global ZPanel Entry then push the "Spacebar" then save it. That will clear out field.
If NOT, login to your PHPmyAdmin as root
Go to: localhost >> zpanel_core >> x_settings >>so_id_pk - 74 and 87 edit the entry of so_value_tx then save it.
Make sure that the so_id_pk 74 & 87 is Global VHost Entry and Global ZPanel Entry