diff --git a/frappy/modulebase.py b/frappy/modulebase.py
index 92acc9c4..c47a659e 100644
--- a/frappy/modulebase.py
+++ b/frappy/modulebase.py
@@ -439,8 +439,9 @@ class Module(HasAccessibles):
         if not self.export:  # do not export parameters of a module not exported
             accessible.export = False
         self.accessibles[name] = accessible
-        if accessible.export:
-            self.accessiblename2attr[accessible.export] = name
+        self.setExport(name, accessible.export)
+        # if accessible.export:
+        #    self.accessiblename2attr[accessible.export] = name
         if isinstance(accessible, Parameter):
             self.parameters[name] = accessible
         if isinstance(accessible, Command):
@@ -502,6 +503,19 @@ class Module(HasAccessibles):
             # this checks again for datatype and sets the timestamp
             setattr(self, pname, pobj.value)
 
+    def setExport(self, pname, flag):
+        """change the export flag of a parameter or command
+
+        to be called in "meth:checkProperties() when needed """
+        pobj = self.accessibles[pname]
+        if flag:
+            pobj.export = True
+            pobj.fixExport()
+            self.accessiblename2attr[pobj.export] = pname
+        else:
+            self.accessiblename2attr.pop(pobj.export, None)
+            pobj.export = False
+
     def announceUpdate(self, pname, value=None, err=None, timestamp=None, validate=True):
         """announce a changed value or readerror