code: private void applySettings() {
  		container.reset();
  		// Now show an example of the number of different columns
  
  		WPanel gridLayoutPanel = new WPanel();
  
  		if (cbResponsive.isSelected()) {
  			gridLayoutPanel.setHtmlClass(HtmlClassProperties.RESPOND);
  		}
  
  		GridLayout layout = new GridLayout(rowCount.getValue().intValue(), columnCount.getValue()
  				.intValue(),
  				hGap.getValue().intValue(),
  				vGap.getValue().intValue()
  		);
  
  		gridLayoutPanel.setLayout(layout);
  
  		addBoxes(gridLayoutPanel, boxCount.getValue().intValue()); // give approx 3 rows, with a different number
  		// of boxes on the final row
  		container.add(gridLayoutPanel);
  
  		gridLayoutPanel.setVisible(cbVisible.isSelected());
  	}
docs: reset the container that holds the grid layout and create a new grid layout with the appropriate properties.