@Nullable
 @Override
 public JComponent createComponent() {
   if (mySettingsPane == null) {
     mySettingsPane = new DiffSettingsPanel();
   }
   return mySettingsPane.getPanel();
 }
 @Override
 public void reset() {
   if (mySettingsPane != null) {
     mySettingsPane.reset();
   }
 }
 @Override
 public void apply() throws ConfigurationException {
   if (mySettingsPane != null) {
     mySettingsPane.apply();
   }
 }
 @Override
 public boolean isModified() {
   return mySettingsPane != null && mySettingsPane.isModified();
 }