docs: private void themeComboBoxActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_themeComboBoxActionPerformed
          String themeName = (String)themeComboBox.getSelectedItem();
          String themeClassName = (String)mapThemes.get(themeName);
          if ((themeClassName != null) && (!ScreenUtil.DEFAULT.equalsIgnoreCase(themeClassName)))
              properties.put(ScreenUtil.THEME, themeClassName);
          else
              properties.remove(ScreenUtil.THEME);
  
          ScreenUtil.updateLookAndFeel(this, null, properties);
          this.setSampleStyle();
      }