The Call Graph Query window lets you specify a call graph query.  A
  call graph query graphically displays the relationships between
  symbols, according to the range you specify.  This window lets you
  specify the following attributes:

      o  From-calls from a routine

      o  To-calls to a routine

      o  Depth-the specified number of levels in the call
         graph

  You must specify a reference point to begin a call graph query.  As
  such, you must specify either the From or To attribute, or both.