If you look at shows like Air Crash Investigation, which surely take some creative license in how events are portrayed, they often portray the disappearance of an aircraft, or specifically loss of its transponder return, as the radar return simply disappearing from ATC's radar scopes.
My question is: is that actually the only thing that happens when ATC secondary radar loses an aircraft's transponder return, when the aircraft is not actually on approach to land (and thus losing line of sight to the radar would be normal and expected, and/or that radar return is no longer relevant for air traffic control purposes)?
In general, humans are better at picking out things that are there than they are at picking out things that aren't there, even if they were there previously. It's also very rare for an aircraft to lose its transponder, let alone crash. Therefore, some kind of positive notification that a transponder return was lost when it shouldn't have been, possibly after a short delay (to account for those aircraft where the transponder is set to standby while a new code is being selected) would seem helpful.
Yes, it's the controller's job to keep track of the aircraft they are in charge of, but especially with modern, digital radar systems, it seems like something like flashing a distinct symbol where the aircraft was last seen, or sounding an alert chime, or just about anything, could make their job a lot easier the very few times that an aircraft transponder return disappears when it shouldn't have.