diff -r 235a9ec83b95 -r e12228fd8773 PLCControler.py
--- a/PLCControler.py	Thu Nov 15 23:00:53 2012 +0100
+++ b/PLCControler.py	Thu Nov 15 23:04:41 2012 +0100
@@ -1644,6 +1644,8 @@
     def IsLocatableType(self, type, debug = False):
         if isinstance(type, TupleType):
             return False 
+        if self.GetBlockType(type) is not None:
+            return False
         project = self.GetProject(debug)
         if project is not None:
             datatype = project.getdataType(type)