Bug 113938 Report is marked dirty when open/close cascading parameter dialog without doing any operation on it
description: Report is marked dirty when open/close cascading parameter dialog without doing any operation on it steps to reproduce: 1.new a cascading parameter group 2.save the reprot 3.double click the cascading parameter to bring out edit box 4.click OK to close edit box actual result: Report has been marked dirty expected result: No dirty marked for that no operations done in edit parameter dialog
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
* Gets the proper expression for the given model
	 * 
	 * @param model
	 *            the given model
	 * @return Returns the proper expression for the given model, or null if no
	 *         proper one exists
	 */
	public static String getExpression( Object model )
	{
		if ( model instanceof ParameterHandle )
		{
			return IReportElementConstants.PARAMETER_PREFIX
					+ "[\"" + ( (ParameterHandle) model ).getQualifiedName( ) + "\"]"; 
		}
		if ( model instanceof DataSetItemModel )
		{
			String colName = ( (DataSetItemModel) model ).getAlias( );
			if ( colName == null || colName.trim( ).length( ) == 0 )
			{
				colName = ( (DataSetItemModel) model ).getName( );
			}
			return getColumnExpression( colName );
		}
		return null;
	}
	/**
	 * Returns the integer font size for string value.
	 * 
	 * @param fontSize
	 * @return