diff -r 0b6ab74f4b89 -r b0d6819119c3 TextViewer.py
--- a/TextViewer.py	Wed Jun 29 12:29:14 2011 +0200
+++ b/TextViewer.py	Mon Jul 04 15:24:44 2011 +0200
@@ -344,6 +344,9 @@
                 blockname = blocktype["name"].upper()
                 if blocktype["type"] == "function" and blockname not in self.Keywords and blockname not in self.Variables.keys():
                     interface = dict([(name, {}) for name, type, modifier in blocktype["inputs"] + blocktype["outputs"] if name != ''])
+                    for param in ["EN", "ENO"]:
+                        if not interface.has_key(param):
+                            interface[param] = {}
                     if self.Functions.has_key(blockname):
                         self.Functions[blockname]["interface"].update(interface)
                         self.Functions[blockname]["extensible"] |= blocktype["extensible"]