Apart from displaying elements hierarchically, you can also build a hierarchy by nesting additional elements within the selected element directly in the table. The Complete tree view is enabled in the table by default. 

To build a custom hierarchy 

Do one of the following:

• In the table, right-click the specific element to nest an additional element within, select Add Nested in the drop-down menu, and specify the type of the element to create, e.g., Requirement. 
  
  
  
• Select the specific table element to nest an additional element within, click the Add Nested button in the table toolbar, and specify the type of the element to create, e.g., Requirement.