Bug 122854 There is redundant columns in "available columns" list in "export data" dialog.
Description: There is redundant columns in "available columns" list in "export data" dialog. Steps to reproduce: 1. Preview attached design in web viewer. 2. Select the table and click on "export" button. 3. There is a "detail" column name in "available columns" list which is not data set column.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/data/dte/ReportQueryBuilder.java
IGroupDefinition groupDefn = handleGroup( group, handle );
			pushQuery( groupDefn );
			pushExpressions( groupDefn.getBeforeExpressions( ) );
			handleTableBand( group.getHeader( ), value );
			popExpressions( );
			pushExpressions( groupDefn.getAfterExpressions( ) );
			handleTableBand( group.getFooter( ), value );
			popExpressions( );
			popQuery( );
		}
		/**
		 * handle style, which may contain highlight/mapping expressions
		 * 
		 * @param style
		 *            style design
		 */
		protected void handleStyle( IStyle style )
		{
			/*
			 * if ( style != null ) { handleHighlight( style.getHighlight( ) );
			 * handleMap( style.getMap( ) ); }
			 */
		}
		/**
		 * handle mapping expressions
		 */
		protected void handleMapExpressions( MapDesign map )
		{
			if ( map != null )
			{