If some of your ships wants to speak with you and you are in the map view,
if you press "M" button (close map) instead of "F" (answer) - then after the time out without answering,
the orange dialog Frame will blink empty forever.
Image attached:

It will disapear only if someone will call you again.
Fastest way is to send any ship to any station with command "dock to trade", he we call you after docking.