@Override
  protected void update() {
    if(myCbToSearchForTextOccurrences != null){
      updateStateOnUsagesStateChange(myCbToSearchForTextOccurrences);
    }

    boolean hasSelected = isSelected(myCbUsages) ||
      isSelected(myCbFieldsUsages) ||
      isSelected(myCbMethodsUsages) ||
      isSelected(myCbImplementingClasses) ||
      isSelected(myCbDerivedInterfaces) ||
      isSelected(myCbDerivedClasses);
    setOKActionEnabled(hasSelected);
  }
@Override
  protected void update()