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.tests/test/org/eclipse/birt/report/model/api/HighlightRuleHandleTest.java
designHandle.getCommandStack( ).undo( );
		
		
		style2Highlight.setStyle( style3 );
		assertEquals( style3, style2Highlight.getStyle( ) );
		refs = ( (ReferenceableElement) style1.getElement( ) ).getClientList( );
		assertEquals( 0, refs.size( ) );
		
		refs = ( (ReferenceableElement) style3.getElement( ) ).getClientList( );
		assertEquals( 1, refs.size( ) );
		assertEquals( "My Style2", ref1.getElement( ).getName( ) ); 
		assertEquals( "highlightRules", ref1.getPropertyName( ) ); 
		style2Highlight.setStyle( null );
		assertNull( style2Highlight.getStyle( ) );
		assertNull( style2Highlight
				.getStringProperty( HighlightRule.STYLE_MEMBER ) );
		
		try
		{
			style2Highlight.setStyle( style2 );
			fail( );
		}
		catch ( SemanticException e )
		{
			assertEquals(
					SemanticError.DESIGN_EXCEPTION_CIRCULAR_ELEMENT_REFERNECE,
					e.getErrorCode( ) );
		}
		Iterator style3HighlightRules = style3.highlightRulesIterator( );
		assertTrue( style3HighlightRules.hasNext( ) );