Constraints not working

In v3, I never seemed to need constraints, as it was not easy to drag an object completely off screen.  Now, however, dragging using the "follow me" behavior seems very uneven, sometimes following nicely and sometimes letting you fling the object completely off-screen.  Sometimes it even seems to send the object in the wrong direction (opposite the way you are trying to drag it).  I was hoping to fix this somewhat by constraining the area to the dimensions of the screen, but this does not seem to work--I can still fling the object completely off screen.