DragRigidbody behavior attached to multiple rigid bodies causes problems

I have a prefab crate which has the DragRigidbody behavior attached to it. If I have only one crate on the scene, dragging and dropping it is absolutely perfect. As I start adding crates however, I noticed that while dragging still works, dropping a crate causes it to stay mid-air for a long period if time. It still fals, but for a 10 times larger period ... it basically floats mid-air. Although I am a Unity newbie, I have developed games before, so I assume that there must be some kind of a controller that determines whether an object is being dragged. If there is one, the controller, must go through all the other crates and turn their Drag behavior off until the "active" crate is back on the floor. If there's something I'm missing ... a better way to do it, for instance, I will e glad to know about it.