Dungeon (World) class is now cleared from game object maps. Yes, they were there, because object maps are just 'temp' pointers to the object, which are owned by the Level class in a linked list container. The map could also own these objects, but it would need dramatic changes in the way true object handles (vs. generic base class handle) are stored.
At that point I was able to run the game, but it wasn't very pretty to look at. Terrain tiles were missing, because Level::Show is now in Tile_Map class and terrain isn't there yet. The game also crashed a lot which is funny, because the usual code is rock solid. I believe it will sort out itself when everything is moved to their proper locations.
Terrain and masks are the big refactoring thing I'm now programming. It's more tedious than difficult, but some constructions are very different than before. Yet as I thought functions of Tile are shorter and easier to read as source code, because they don't require external gets from different map layers.