If the link to the event is selected by the user, then {HEAD ~ that event} is made {TAIL ~ the current event} in the user interface and the other windows are updated accordingly 
If the link to the event is selected by the user , then { HEAD ~ that event } is made { TAIL ~ the current event } in the user interface and the other windows are updated accordingly
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH