Why QGC display "waiting for vehicle connection " when i run mavlink/examples/linux/mavlink_udp on a computer

os env : ubuntun 16.4

  1. run mavlink/examples/linux/mavlink_udp
  2. run QGC3.5.4

but QGC display "waiting for vehicle connection " , but qgc mavlink inpector can find received data

do any body know why

do any body use mavlink/examples/linux/mavlink_udp to simulation qgc connected?