@Override
  public boolean canCopy(PsiElement[] elements, boolean fromUpdate) {
    String propertyName = null;
    for (PsiElement element : elements) {
      final IProperty property = PropertiesImplUtil.getProperty(element);
      if (property == null) {
        return false;
      }
      else if (propertyName == null) {
        propertyName = property.getKey();
      }
      else if (!propertyName.equals(property.getKey())) {
        return false;
      }
    }
    return propertyName != null;
  }
@Override
  public boolean canCopy(PsiElement[] elements, boolean fromUpdate)