I realize it has been nearly a year since your post but I was just having the same problem with 2008, which I just started using at a new job on a new machine. It turns out it is not so much a Lectora setting but rather it is how you adjust your Mouse settings for your machine. If you go into your control pannel and change the "double click" speed to a faster speed then you should be able to toggle an objects visibility more rapidly.
