Terrain Builder - Elevation locks model in Buldozer.
If you add models to example layer "Test". Then you select one of the model and change elevation mode to "keep absolute position", you cant select that model in Buldozer anymore. You need go to Terrain Builder to select model.
What's even more annoying with this feature, is when you forget which layer this object is on and have to go one by one and hope you don't have multiple objects placed on the same layer as you try to click it in terrain builder!
Don't ask me how many times I've done this, usually accidentally when moving an object to another layer and clicking my mouse button right as it moves to another option......