You can view and verify the traceability of an item by looking at the reference dialog icon:
In case a trace is missing the reference dialog icon of the item will be red: 

In case the item has some suspicious references, it will be orange: 



If you click on the reference dialog icon the Reference Dialog opens:


In the dialog you can

  • create new items by clicking on the box with red text inside or
  • click on existing references to expand the tree
  • double clicking on existing references to open a referred item
  • add references (up or down-traces) by clicking on "Select"