You can turn on audit logging which will show you which sheets a user accesses, and also what selections they make, so there would be ways around doing what you're after - you could hide a particular object unless a user clicked on a given button for example, or you could put the given item on it's own sheet which would therefore give you the same idea, but unfortunately there isn't information down past that granularity level, so object based "activation" isn't available - you often get the difficulty that even though a user may be "using" an object, you wouldn't know it unless they interacted with it!
