Gravity Toggle for item placement

This would be the ability to toggle an option that would make any floating objects fall. They would be allowed to fall until they reach the highest Y coordinate.
This will cause a second issue with people not wanting items to float, falls, move, ect, we really need the ability to lock an object.

Ive ran into this issue many times placing pebbles, rocks, anything small. The smallest elevation it becomes a tedious mess fixing all the items so they sit correctly in the mesh.