code: protected Composite createCommonControls(Composite parent) {
  		initializeDialogUnits(parent);
  		final Composite composite = SWTFactory.createComposite(
  				parent,
  				parent.getFont(),
  				COLUMNS, 1,
  				GridData.FILL_HORIZONTAL);
  		createContainerControls(composite, COLUMNS);
  		createPackageControls(composite, COLUMNS);
  		createSeparator(composite, COLUMNS);
  		createTypeNameControls(composite, COLUMNS);
  		return composite;
  	}
docs: Create the components that are common to the creation of all
  the SARL elements.
  
  <p>You should invoke this from the {@link #createControl(Composite)} of
  the child class.
  
  @param parent the component in which the common controls are added.
  @return the created composite.