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
}
			if ( intervalBaseText.getEnabled( ) )
			{
				inputGroup.setIntervalBase( UIUtil.convertToModelString( intervalBaseText.getText( ),
						false ) );
			}
			else
			{
				inputGroup.setIntervalBase( null );
			}
			inputGroup.setHideDetail( hideDetail.getSelection( ) );
			if ( inputGroup instanceof TableGroupHandle )
			{
				if ( includeHeader.getSelection( ) != inputGroup.hasHeader( ) )
				{
					if ( includeHeader.getSelection( ) )
					{
						inputGroup.getHeader( ).add( createRow( ) );
					}
					else
					{
						inputGroup.clearContents( GroupHandle.HEADER_SLOT );
					}
				}
				if ( includeFooter.getSelection( ) != inputGroup.hasFooter( ) )
				{
					if ( includeFooter.getSelection( ) )
					{
						inputGroup.getFooter( ).add( createRow( ) );
					}