The drilldown view indicates the relative size and contained XS at the current scope of drill-down in your code.
The total length of the line to the right of each item indicates the relative amount of code contained by that item. The red portion of the line indicates the amount of excess complexity (XS) as defined by the current XS Configuration.
Selecting an item in the Drilldown list updates the information in the other views.
Double-click on any node in the Drilldown to navigate to the next level of composition. Use the "up" arrow on the tool bar to move back up in the composition hierarchy.