Suppose your cursor is on a class name in a class definition, or on the name of one of its members, and you want to see the hierarchy of classes this class or member inherit from, or the hierarchy of inheriting classes / overriding methods of the same name. What Action in CLion lets you do that?
It's Ctrl+H (which corresponds to View > Tool windows > Hierarchy).
Unfortunately, the display of the hierarchy doesn't work everytime.