Actually, the "little color screen" only shows the aircraft that have the necessary transmitter to talk to the "little color screen;" many don't.   I know boats better than planes but the technology and rules are much the same.   In VFR conditions, apparently the situation here, the most important navigational tool is the Mark 1- A1 Eyeball.   One pilot or the other lost what is euphemistically called "situational awareness."   There is a reason that when you seek a license to operate an airplane or a boat, they make you learn how to do it with NO electronic aids.   The electronics make it easier, but they also make you lazy and careless.   I ran the investigation of the allusion of M/V LeConte with Cozian Reef on a beautiful cloudless day; the last words from the deck officers were, "I lost situational awareness."  There is no substitute for the Mk.1-A1 Eyeball.