code: public void setReasonVariantsDisabled(String reason) {
          reasonVariantsDisabled = Objects.requireNonNull(reason);
  
          labelReasonVariantsDisabled.setText(reasonVariantsDisabled);
          if (reasonVariantsDisabled.isEmpty() && labelReasonVariantsDisabled.isVisible()) {
              labelReasonVariantsDisabled.setVisible(false);
          }
      }
docs: Sets the reason to show when the the variants are disabled.
  
  @param reason the reason that indicates why the variants are disabled.
  @since TODO add version
  @throws NullPointerException if the given {@code reason} is {@code null}.
  @see #setAllInjectableAndRPC(boolean)