If you manually add import statements for importing objects that you will use on the map during the game but are not actually existent on the map, the editor will remove them from the map upon saving.
You should be able to import all objects that you will use during runtime and that done necessarily have a place on the map. An example is the shooter demos bullets.
Copied from original issue: fifengine/fifengine#468
From @prock-fife on May 19, 2010 0:42
If you manually add import statements for importing objects that you will use on the map during the game but are not actually existent on the map, the editor will remove them from the map upon saving.
You should be able to import all objects that you will use during runtime and that done necessarily have a place on the map. An example is the shooter demos bullets.
Copied from original issue: fifengine/fifengine#468