Ok, let's see how to view the hierarchy...

The process must be the following:
- Know the current class
- Find all the 'references' for that class
- For each reference see if it appears in a class definition
- etc.


To display it we should always have:
1. The current class we're seeing 
2

Examples to see better:
CenterExample (how to center)
TooltipExample
NodeLinkExample
LayoutExample

