private void VolumeCheckBoxActionPerformed(
      java.awt.event.ActionEvent evt) { // GEN-FIRST:event_VolumeCheckBoxActionPerformed
    // if user de-select volume of size
    if (!VolumeCheckBox.isSelected()) {
      // select the detail checkbox
      DetailSizeCheckBox.setSelected(true);

      // disable the volume text field
      VolumeTF.setEnabled(false);
      VolumeTF.setText("");
      VolumeLabel.setText("Volume : ");

      // reenable the detail of size text field
      LengthTF.setEnabled(true);
      LengthLabel.setText("* Length : ");
      WidthTF.setEnabled(true);
      WidthLabel.setText("* Width : ");
      HeightTF.setEnabled(true);
      HeightLabel.setText("* Height : ");
    } else {
      // dis-select the detail checkbox
      DetailSizeCheckBox.setSelected(false);

      // empty the detail text field and disable it
      LengthTF.setText("");
      LengthTF.setEnabled(false);
      LengthLabel.setText("Length : ");
      WidthTF.setText("");
      WidthTF.setEnabled(false);
      WidthLabel.setText("Width : ");
      HeightTF.setText("");
      HeightTF.setEnabled(false);
      HeightLabel.setText("Height : ");

      // reenable volume text field
      VolumeTF.setEnabled(true);
      VolumeLabel.setText("* Volume : ");
    }
  } // GEN-LAST:event_VolumeCheckBoxActionPerformed