I am converting from using a Notebook organizational system to using tags due to the ability to nest tags to several levels. When I am in the "Tag" view, looking at all of my tags and beginning to nest "child" tags underneath "parent" tags (by dragging), I am finding that sometimes EN won't allow the nesting. I have tried to figure out when it will and when it won't allow this (e.g. no nesting under tag with zero occurrences OR no nesting two more levels without an occurrence OR ...), but I am not finding a rhyme or reason for the issue. It just will not allow me to nest some tags while other tags nest without a problem. Please help me. What are the rules for when you can and cannot nest one tag under another? Where can I find these rules? Using Evernote 6.0.3 on MacBook Pro. Thanks!