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
* @return The corresponding <code>StyleDesign</code> object.
	 */
	public IStyle findStyle( String name )
	{
		if ( name == null )
		{
			return null;
		}
		return (IStyle) this.styleTable.get( name );
	}
	/**
	 * Appends a top-level parameter or parameter group in the report.
	 * 
	 * @param parameter
	 *            The parameter or parameter group object.
	 */
	public void addParameter( IParameterDefnBase parameter )
	{
		assert ( parameter != null );
		assert ( parameter.getName( ) != null );
		this.parameters.add( parameter );
	}
	/**
	 * Finds a master page with given name.
	 * 
	 * @param name
	 *            The name of the master page to locate.
	 * @return A <code>MasterPageDesign</code> object that describes the
	 *         master page, or <code>null</code> if no master page of the
	 *         given name is found.