I struggled with this for a long time, but I couldn't quite get it right. I did everything correctly, it seems, and I inserted the script `MessageBox("/Maps/SingleMissions/ExampleMap/msg.txt");`, but it appears as soon as the game starts, not when I approach the designated area! Without the script, it doesn't work at all!
Here's a picture:

Please check if it works on your computer!
And tell me if it works for you the way it doesn't work for me????
If it works for you, I'll send you my map, and you can check it, okay???
Thank you for your response, Pobeditel!!!