You just started working on a project and the CAD files are all over the place. You open up your XREF manager by typing XR and notice that there are numerous XREFs that can't be detached. These are nested XREFs, meaning they have been attached in other drawings and must be detached in that specific drawing.
Now the question is how to find which drawing that nested XREF belongs to. When you are in XREF manager simply hit F4 to enter into Tree View. This view shows you exactly what files belong to specific XREFs. This is extremely helpful for removing nested XREFs and also figuring out where large, obsolete JPEGs are located so they can be deleted and reduce overall file size.
To return to List View in the XREF manager simply hit F3. This is a quick trick that will save you lots of time and help to better organize your CAD file structure.