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
* @return
	 */
	public static boolean isSameString( String str1, String str2 )
	{
		if ( str1 == null && str2 == null )
		{
			return true;
		}
		if ( str1 != null && str1.equals( str2 ) )
		{
			return true;
		}
		return false;
	}
	/**
	 * Create a row expression base on column name.
	 * 
	 * @param columnName
	 * @return
	 */
	public static String getColumnExpression( String columnName )
	{
		Assert.isNotNull( columnName );
		if ( StringUtil.isBlank( columnName ) )
		{
			return null;
		}
		return IReportElementConstants.DATA_COLUMN_PREFIX
				+ "[\"" + DEUtil.escape( columnName ) + "\"]";
	}