code: private void addHgapVGapExample(final Size hgap, final Size vgap) {
  		add(new WHeading(HeadingLevel.H2, "Column Layout: hgap=" + hgap.toString() + " vgap=" + vgap.toString()));
  		WPanel panel = new WPanel();
  		panel.setLayout(new ColumnLayout(new int[]{25, 25, 25, 25}, hgap, vgap));
  		add(panel);
  
  		for (int i = 0; i < 8; i++) {
  			panel.add(new BoxComponent("25%"));
  		}
  
  		add(new WHorizontalRule());
  	}
docs: Build an example using hgap and vgap.
  
  @param hgap the hgap width
  @param vgap the vgap width