what the map is doing when you dont have objects its reading the temp file. The temp file records objects and water you have used in a previous map before hand. So when testing the map it adds all the objects from the temp file into your different map for some reason. I've been messing about with map maker lately and thats what i ended up noticing. When people say adding a object into your map before testing helps prevent that its true because now the temp file should be reading new objects.
However going into the temp file and deleting all the object codes out of it doesnt work. When you load up the game they still appear.
(i know this because i spent hours messing about with the creator. Heres what i mean, this is whats in my temp file)
[Map]
Name=MM
Seed=G1Ps0j7wjm
[Terrain]
Filename=tempTerrain.cfg
Size=30000 30000
Boundary=0
[Sky]
HasSky=true
Filename=Day (Top)
[Water]
Ocean=15000 320 15000
OceanSize=36000 36000
[MapMaker]
StartPos=10883.3 998.263 12177.9
[Objects]
Filename=tempObjects.cfg
[Gates]
[Weather]
Filename=Rain
[Portal]
HasPortal=true
Position=10283 349 8762
Yaw=342
Now if i decided to make another map and hit test all these will show up. Floating plants and water or way under the map.