Bug 121287 Post BIRT M3 build: Edit Group Dialog does not present expression builder for Group On
In Edit Group dialog, there is no expression builder for the Group On field. In order to support multi-pass aggregation, the expression builder is needed to specify an expression to group on.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/GroupDialog.java
private GroupHandle inputGroup;
	/**
	 * The name editor
	 */
	private Text nameEditor;
	/**
	 * The group key and interval type combo box.
	 */
	private Combo keyChooser, intervalType;
	/**
	 * The spinner to choose interval range;
	 */
	private Spinner intervalRange;
	private FormPage filterPage, sortPage;
	/**
	 * The include check box and sorting direction radio box
	 */
	private Button includeHeader, includeFooter, ascending, descending;
	private Text tocEditor;
	final private static IChoice[] intervalChoices = DesignEngine.getMetaDataDictionary( )
			.getChoiceSet( DesignChoiceConstants.CHOICE_INTERVAL )
			.getChoices( );
	final private static IChoice sortByAscending = DesignEngine.getMetaDataDictionary( )
			.getChoiceSet( DesignChoiceConstants.CHOICE_SORT_DIRECTION )
			.findChoice( DesignChoiceConstants.SORT_DIRECTION_ASC );
	final private static IChoice sortByDescending = DesignEngine.getMetaDataDictionary( )
			.getChoiceSet( DesignChoiceConstants.CHOICE_SORT_DIRECTION )
			.findChoice( DesignChoiceConstants.SORT_DIRECTION_DESC );
	final private static String SORT_GROUP_TITLE = DEUtil.getPropertyDefn( ReportDesignConstants.TABLE_GROUP_ELEMENT,
			GroupHandle.SORT_DIRECTION_PROP )