There is no easy way to check for a conflict every time the user is changing
some of the mentioned properties. To disallow such settings would be laborious
and risky and i am not sure if it's worth the effort. 

in this context i changed the code generator so on each place in the code where
a local variable from initComponents()  is used in a listener method outside the
initComponents() scope will be a comment with a warning and a explanation which
settings could be the cause for the compile error.

Checking in Bundle.properties;
/cvs/form/src/org/netbeans/modules/form/Bundle.properties,v  <--  Bundle.properties
new revision: 1.179; previous revision: 1.178
done
Checking in JavaCodeGenerator.java;
/cvs/form/src/org/netbeans/modules/form/JavaCodeGenerator.java,v  <-- 
JavaCodeGenerator.java
new revision: 1.165; previous revision: 1.164
done

It looks like this fix has broken code generation of event listeners.
Now it can generates syntaxtic wrong code:

 private class FormListener implements java.awt.event.ActionListener {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            if (evt.getSource() ==
                // WARNING: Variable jButton1 should not be declared as local in
initComponents() as long as
                // Forms property 'Listener Generation Style' is set to 'Main
Class' or 'One Inner Class'.
                // Check the values set in components 'Use Local Variable' and
                // Forms 'Local Variables' and 'Listener Generation Style'
properties.
                if (evt.getSource() == jButton1) {
                    NewJFrame3.this.jButton1ActionPerformed(evt);
                }
            }
        }// </editor-fold>


It produces wrong code in all cases when Listener Generation Syle is not set do
Annonymous Inner Class

oops!
should be ok now...

Checking in JavaCodeGenerator.java;
/cvs/form/src/org/netbeans/modules/form/JavaCodeGenerator.java,v  <-- 
JavaCodeGenerator.java
new revision: 1.166; previous revision: 1.165
done

verified