One LabVIEW feature that has a bit of a learning curve associated with it is the Tree Control. The concept of unique string 'tags' for each item can confuse some first-time users, especially those who are used to the integer row-based functionality of listboxes. Then you add in the tasks of indenting items, keeping track of parent tags, worrying about items with the same user-visible text...and things start to get more complicated. More often than not, users must maintain their own, tree-like data structure that lives alongside the tree control to keep track of the internal data associated with user-visible data within the tree.
Well, if you're new to the tree control, you might find Norm's Tree Control API to be an easier place to start than with native programming of the tree. Norm's API has VIs that wrap most of the commonly-needed operations on the tree control with an intuitive interface:
Note that I recommend this API for new users of the tree control. If you're already familiar with LabVIEW tree control programming, you probably won't find much in this API that you don't already know how to do with native VI Server programming.