correclty highlight parts_of_same args

app.py

@@ -85,10 +85,13 @@ if __name__ == "__main__":
                 "supports": "#9f9",
                 # red
                 "contradicts": "#f99",
-                # do not highlight
-                "parts_of_same": None,
+                # show in same color as "selected"
+                "parts_of_same": "#ffa",
+            },
+            "head": {
+                # show in same color as "selected"
+                "parts_of_same": "#ffa",
             },
-            "head": None,  # "#faf",
             "other": None,
         },
     }