title: How can I create a Hierarchical block with GNURadio Companion?
body: <p>I am trying to create a Hierarchical block using the GNURadio Companion GUI.  Answers I've found in other posts say to select the blocks you want to incorporate, then go to More -> Create Hier.   Then a new screen is supposed to appear.  However, doing "Create Hier" with any combinations of blocks selected seems to do nothing.</p>
  
  <p>Am I doing something wrong, or is there a problem with my GRC?</p>