Bug 136027 [Smoke]the report with a gounp can not preview
Description: the report with a gounp can not preview Steps to reproduce: 1. new a datasource and a dataset 2. drag the dataset to the layout 3. Add a group on the table. save and preview. Actual result: "Error happened while running the report" is appeared.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/GroupDialog.java
{
			includeGroup.setEnabled( false );
			includeHeader.setEnabled( false );
			includeFooter.setEnabled( false );
		}
		Group sortingGroup = new Group( composite, SWT.NONE );
		sortingGroup.setText( SORT_GROUP_TITLE );
		sortingGroup.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		sortingGroup.setLayout( new FillLayout( SWT.VERTICAL ) );
		Composite sortingGroupComposite = new Composite( sortingGroup, SWT.NONE );
		sortingGroupComposite.setLayout( new GridLayout( ) );
		ascending = new Button( sortingGroupComposite, SWT.RADIO );
		ascending.setText( sortByAscending.getDisplayName( ) );
		descending = new Button( sortingGroupComposite, SWT.RADIO );
		descending.setText( sortByDescending.getDisplayName( ) );
		Group pagebreakGroup = new Group( composite, SWT.NONE );
		
		pagebreakGroup.setText( Messages.getString( "GroupDialog.PageBreak" ) ); 
		pagebreakGroup.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		GridLayout layout = new GridLayout( );
		layout.numColumns = 2;
		pagebreakGroup.setLayout( layout );
		
		new Label( pagebreakGroup, SWT.NONE ).setText( Messages.getString( "GroupDialog.PageBreakBefore" ) ); 
		pagebreakBeforeCombo = new Combo( pagebreakGroup, SWT.NONE );
		for ( int i = 0; i < pagebreakBeforeChoicesAll.length; i++ )
		{
			pagebreakBeforeCombo.add( pagebreakBeforeChoicesAll[i].getDisplayName( ) );
		}
		pagebreakBeforeCombo.setData( pagebreakBeforeChoicesAll );