Large Bullhorn - how long?

[R28712271]

How long should a large bullhorn last? I've seen some messages up for many hours, but I posted one a couple of hours ago, and it disappeared after I rebooted my PC just now. There is no other message in its place.
Thanks in advance for any insight into this!

[CondorHero]

It will be on YOUR screen as long as you don't refresh.

It shows up on the screen of the players when they don't refresh it.

[R28712271]

Brilliant, thank you CondorHero - I wondered if my reboot had anything to do with it. Much obliged.

[KnowingEyes7]

Brilliant, thank you CondorHero - I wondered if my reboot had anything to do with it. Much obliged.

Corollary: Anyone else who uses one will override yours. This includes manual staff announcements.