title: Eclipse development - change FieldEditor based on new value of other FieldEditor inside FieldEditorPreferencePage
body: <p>In <a href="https://github.com/Nodeclipse/nodeclipse-1/blob/master/org.nodeclipse.ui/src/org/nodeclipse/ui/preferences/NodePreferencePage.java" rel="nofollow">Nodeclipse preference Page</a>
  I want that expressVersion is updated when expressPath is changed.</p>
  
  <p>I am adding code below, however it does not fire PropertyChangeEvent so this logic does not get executed.<br>
  What is wrong here?</p>
  
  <pre><code>    expressPath = new FileFieldEditor(PreferenceConstants.EXPRESS_PATH, "Express path:", getFieldEditorParent());
      //TODO update expressVersion on expressPath selection
      IPropertyChangeListener listener = new IPropertyChangeListener() {
          @Override
          public void propertyChange(PropertyChangeEvent event) {
              if (event.getProperty().equals(FieldEditor.IS_VALID)) {
                  String newValue = (String) event.getNewValue();
                  expressVersion.setStringValue( ProcessUtils.getCurrentVersionOf(newValue) );
              }
          }               
       };
      expressPath.setPropertyChangeListener(listener);
      addField(expressPath);
  
      expressVersion = new StringFieldEditor(PreferenceConstants.EXPRESS_VERSION, "Selected Express version:", getFieldEditorParent());
      expressVersion.setEnabled(false, getFieldEditorParent());
      addField(expressVersion);        
  </code></pre>