Try as I might I cannot get what seems to be extra vertical space between nodes to tighten up.  I think the fm wants to keep a given node from being vertically overlapped with any other node to the "right" of it at any level but in my case, I can't see why it will not let me move the circled nodes up (see image).  Thoughts?  Also, is there any possible way to allow nodes to "tuck" up/down so that they overlap with other nodes that are farther out on the tree.  This would be really nice and I see no reason it can't be done.  Image: