Bug 166015 Refactor designer actions to eclipse command framework
Eclipse command framework provide a more explicit way to manage UI actions contributions, we can take it's advantage to make our actions code more clean and maintainable.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/editors/schematic/actions/InsertGroupActionFactory.java
{
	private static final String STACK_MSG_ADD_GROUP = Messages
			.getString( "AddGroupAction.stackMsg.addGroup" ); 
	private Object currentModel;
	private List selection;
	protected static final int POSITION_TOP_LEVEL = 0;
	protected static final int POSITION_INNERMOST = -1;
	protected InsertPositionGroupAction( List selection, String text )
	{
		super( );
		this.selection = selection;
		setText( text );
	}
	public void setSelection( List selection )
	{
		this.selection = selection;
		this.currentModel = null;