(Mac version 2.50.2)
Normally, to set up a treasure chest you set the room type to Special Item, then set the Special Item to the contents of the chest (let's say a Shield). This works fine.
However, I also want a Message String to play every time you enter this room.
But when I add a Guy set to "Empty" and a Message String to that same room, then the item is drawn in center of the room when I enter, regardless of where I place the chest. After taking the Shield (from the center of the room or the chest) the string will never appear again.
So then I set the Special Item to "none" and the Room Type to "none", and when I test it out again, not only does the chest work properly this time, but the Message String also appears every time I enter the room.
So, using this "method" I achieved exactly what I wanted, but I wonder if it's a bug because the file isn't saving the fact that I set the Special Item to "none". Part of me wants to believe this was left in as a workaround to have both a chest and a reappearing Message String on the same screen, but it also seems likely that not saving the Special Item as "none" is probably a bug. So I thought I'd mention it.