code: public Packer setFillBoth(final boolean how) {
          if (how == true) {
              gc.fill = GridBagConstraints.BOTH;
              gc.weightx = 1;
              gc.weighty = 1;
          } else {
              gc.weightx = 0;
              gc.weighty = 0;
              gc.fill = 0;
          }
          setConstraints(comp, gc);
          return this;
      }
docs: Add fill=BOTH, weightx=1, weighty=1 to the constraints for the current
  component if how == true, fill=0, weightx=0, weighty=0 if it is false.