diff --git a/graphkit/network.py b/graphkit/network.py
index e4957d59..f81632e9 100644
--- a/graphkit/network.py
+++ b/graphkit/network.py
@@ -293,6 +293,8 @@ def _collect_unsatisfied_operations(self, dag, inputs):
                     # Prune operations that ended up providing no output.
                     unsatisfied.append(node)
                 else:
+                    # It's ok not to dig into edge-data("optional") here,
+                    # we care about all needs, including broken ones.
                     real_needs = set(n for n in node.needs
                                      if not isinstance(n, optional))
                     if real_needs.issubset(op_satisfaction[node]):
@@ -334,7 +336,7 @@ def _prune_graph(self, outputs, inputs):
         dag = self.graph
 
         # Ignore input names that aren't in the graph.
-        graph_inputs = iset(dag.nodes) & inputs  # preserve order
+        graph_inputs = set(dag.nodes) & set(inputs)  # unordered, iterated, but ok
 
         # Scream if some requested outputs aren't in the graph.
         unknown_outputs = iset(outputs) - dag.nodes
@@ -373,7 +375,7 @@ def _prune_graph(self, outputs, inputs):
         # Clone it so that it is picklable.
         pruned_dag = dag.subgraph(broken_dag.nodes - unsatisfied).copy()
 
-        return pruned_dag, tuple(broken_edges)
+        return pruned_dag, broken_edges
 
     def compile(self, inputs=(), outputs=()):
         """
@@ -644,6 +646,7 @@ def _execute_thread_pool_barrier_method(self, inputs, solution, overwrites,
             if len(upnext) == 0:
                 break
 
+            ## TODO: accept pool from caller
             done_iterator = pool.imap_unordered(
                 (lambda op: (op, self._call_operation(op, solution))), upnext)
 
diff --git a/graphkit/plot.py b/graphkit/plot.py
index 19b1cdeb..b41ea99f 100644
--- a/graphkit/plot.py
+++ b/graphkit/plot.py
@@ -251,7 +251,7 @@ def get_node_name(a):
                 # kw["tooltip"] = str(solution.get(nx_node))  # not working :-()
             node = pydot.Node(name=nx_node, shape=shape, **kw)
         else:  # Operation
-            kw = {}
+            kw = {"fontname": "italic"}
 
             if steps and nx_node in steps:
                 kw["penwdth"] = steps_thickness
@@ -337,6 +337,7 @@ def render_pydot(dot, filename=None, show=False):
 
     See :meth:`Plotter.plot()` for sample code.
     """
+    # TODO: research https://plot.ly/~empet/14007.embed
     # Save plot
     #
     if filename:
@@ -381,10 +382,10 @@ def legend(filename=None, show=None):
         subgraph cluster_legend {
         label="Graphkit Legend";
 
-        operation   [shape=oval];
-        graphop     [shape=egg label="graph operation"];
-        insteps     [penwidth=3 label="execution step"];
-        executed    [style=filled fillcolor=wheat];
+        operation   [shape=oval fontname=italic];
+        graphop     [shape=egg label="graph operation" fontname=italic];
+        insteps     [penwidth=3 label="execution step" fontname=italic];
+        executed    [style=filled fillcolor=wheat fontname=italic];
         operation -> graphop -> insteps -> executed [style=invis];
 
         data    [shape=rect];