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/ir/Report.java
/**
	 * A collection that stores the top level report parameters and parameter
	 * groups.
	 */
	protected ArrayList parameters = new ArrayList( );
	/**
	 * queries used by this report.
	 * 
	 * @see org.eclipse.birt.report.engine.anlyzer.IQueryDefinition
	 */
	protected ArrayList queries = new ArrayList( );
	/**
	 * use to find the query IDs.(query, string) pair.
	 */
	protected HashMap queryIDs = new HashMap( );
	/**
	 * Page setup this report used
	 */
	protected PageSetupDesign pageSetup = new PageSetupDesign( );
	/**
	 * Report body
	 */
	protected ArrayList contents = new ArrayList( );
	protected Map namedExpressions;
	
	protected Map mapReportItemIDtoInstance;
	
	/**
	 * The base directory of the relative links. By default it is where design
	 * file (XML) resides