--- a/ConfigTreeNode.py	Fri Mar 22 13:45:19 2019 +0100
+++ b/ConfigTreeNode.py	Fri Mar 22 14:00:35 2019 +0100
@@ -127,7 +127,7 @@
         # TODO match config's fields name and fields contents
         return reduce(add, [
             CTNChild.CTNSearch(criteria)
-            for CTNChild in self.IterChildren()])
+            for CTNChild in self.IterChildren()],[])
 
     def GetIconName(self):
         return None