Bug 206850 [Regression] Error pops up when select value for a map or highlight rule to group header row [0302]
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/elements/structures/StyleRule.java
public static final String VALUE1_MEMBER = "value1"; 
	/**
	 * Name of the property that gives the expression for the second operator
	 * operand.
	 */
	public static final String VALUE2_MEMBER = "value2"; 
	/**
	 * The expression for this rule.
	 */
	public static final String TEST_EXPR_MEMBER = "testExpr"; 
	/**
	 * Status that determines whether this structure is used in design time or
	 * not
	 */
	public static final String IS_DESIGN_TIME_MEMBER = "isDesignTime"; 
	/**
	 * The comparison operator. Default value is <code>MAP_OPERATOR_EQ</code>
	 */
	protected String operator = null;
	/**
	 * Expression for the first operand.
	 */
	protected List value1 = null;
	/**
	 * Expression for the second operand.
	 */
	protected String value2 = null;
	/**
	 * the test expression for this highlight rule.
	 */