Run configuration is never saved

I am writing a plugin for CLion that adds a run configuration type to run an ISO in QEMU.

The problem is that when changes are made to the run configuration editor, the IDE does not seem to be aware, and the "Apply" button is never enabled. Even if I edit my run configuration, go to another run configuration, edit it, and click "Apply", once I close and re-open the run configurations dialog, all changes to my run configuration are lost.

Moreover, in debugging, I noticed that the `Settingseditor#applyEditorTo` method is called repeated about twice a second. It is my understanding that that method is called when changes are applied, no?

Here is my editor code:

// I hate Swing...
public class QemuRunConfigurationEditor extends SettingsEditor<QemuRunConfiguration> {

  // Constructors
  //--------------------------------------------------

  public QemuRunConfigurationEditor(final Project project) {
    super();

    this.project = project;
  }

  // Fields
  //--------------------------------------------------

  private final Project project;

  private Border qemuExecutableFieldDefaultBorder;

  private Border qemuExecutableFieldErrorBorder;

  // UI components
  //--------------------------------------------------

  private JPanel rootPanel;

  // TODO: Allow custom items.
  private JComboBox<String> qemuExecutableField;

  private JRadioButton cmakeTargetRadio;

  private JComboBox<CMakeTarget> cmakeTargetField;

  private JRadioButton cdromFileRadio;

  private TextFieldWithBrowseButton cdromFileField;

  // SettingsEditor methods
  //--------------------------------------------------

  @Override
  protected final void resetEditorFrom(final QemuRunConfiguration runConfig) {
    qemuExecutableField.setSelectedItem(runConfig.getQemuExecutable());

    switch(runConfig.getDiskImageSource()) {
      case CMAKE_TARGET:
        cmakeTargetRadio.doClick();
        break;
      case CDROM_FILE:
        cdromFileRadio.doClick();
        break;
    }

    cmakeTargetField.setSelectedItem(runConfig.getCMakeTarget());
    cdromFileField.setText(runConfig.getCdromFile());
  }

  @Override
  protected final void applyEditorTo(final QemuRunConfiguration runConfig) throws ConfigurationException {
    runConfig.setQemuExecutable((String)qemuExecutableField.getSelectedItem());

    if(cmakeTargetRadio.isSelected()) {
      runConfig.setDiskImageSource(QemuRunConfigurationOptions.DiskImageSource.CMAKE_TARGET);
    } else if(cdromFileRadio.isSelected()) {
      runConfig.setDiskImageSource(QemuRunConfigurationOptions.DiskImageSource.CDROM_FILE);
    }

    runConfig.setCMakeTarget((CMakeTarget)cmakeTargetField.getSelectedItem());
    runConfig.setCdromFile(cdromFileField.getText());
  }

  @Override
  protected final JComponent createEditor() {
    qemuExecutableFieldDefaultBorder = qemuExecutableField.getBorder();

    qemuExecutableField.setModel(new DefaultComboBoxModel<>(QemuExecutableFinder.getQemuExecutables().stream()
        .map(File::getAbsolutePath)
        .toArray(String[]::new)));
    qemuExecutableField.addItemListener(this::qemuExecutableFieldChanged);

    cmakeTargetRadio.addActionListener(this::diskImageSourceRadioChanged);
    cdromFileRadio.addActionListener(this::diskImageSourceRadioChanged);

    cmakeTargetField.setModel(new ListComboBoxModel<>(new CMakeBuildConfigurationHelper(project).getTargets()));
    cmakeTargetField.setRenderer(new CMakeTargetCellRenderer());

    return rootPanel;
  }

  // Listener callbacks
  //--------------------------------------------------

  private void qemuExecutableFieldChanged(final ItemEvent event) {
    final String qemuExecutableCandidate = (String)event.getItem();

    new Thread(() -> {
      // TODO: Better way of doing border.
      if(ExecutableUtils.canExecute(qemuExecutableCandidate)) {
        qemuExecutableField.setBorder(qemuExecutableFieldDefaultBorder);
      } else {
        qemuExecutableField.setBorder(BorderFactory.createLineBorder(JBColor.RED));
      }
    }).start();
  }

  private void diskImageSourceRadioChanged(final ActionEvent event) {
    final JRadioButton source = (JRadioButton)event.getSource();

    if(source == cmakeTargetRadio) {
      cmakeTargetField.setEnabled(true);
      cdromFileField.setEnabled(false);
    } else if(source == cdromFileRadio) {
      cmakeTargetField.setEnabled(false);
      cdromFileField.setEnabled(true);
    }
  }

  // CMakeTargetCellRenderer class
  //--------------------------------------------------

  private static final class CMakeTargetCellRenderer extends ListCellRendererWithRightAlignedComponent<CMakeTarget> {

    // Constructors
    //--------------------------------------------------

    private CMakeTargetCellRenderer() {
      super();
    }

    // ListCellRendererWithRightAlignedComponent methods
    //--------------------------------------------------

    @Override
    protected final void customize(final CMakeTarget cmakeTarget) {
      if(cmakeTarget != null) {
        setIcon(cmakeTarget.getIcon());
        setLeftText(cmakeTarget.getName());
      }
    }

  }

}

The full code can be found on GitHub. It is not much.

Thanks to all who took their time to help!