The shift key seem to have no effect for me? It simply brings up the selection box???
I did some more experimenting.
For example, "Large rocks" and "rock" demand their own space but "small rock" can almost be stacked on the bigger rocks because the green circle for "large rocks" is much smaller then the doodad.
Basically it seem that no doodads will allow another doodad into their green circle. Some doodads are much larger then the green circle so those appear to stack but really they don't.
Unless I'm missing something?
Did you hold the shift key while putting them down?
Did you hold the shift key while putting them down?
Works fine for me, map on the bottom.
now it's the shift key. ^_^ happy infinite stacking