Bug 209126 DataException throws out when set highlight condition in sub-report[0302]
Description: Set highlight condition in sub-report, when "select value..." in the highlight dialog, DataException throws out. Build version:2.3.0.v20071108-0800 Steps to reproduce: 1.Get the attached report design file, which contains a sub-report. 2.Select the inner table, and then go to "highlight" tab in the property editor view to set a highlight rule. When click "select value...", DataException throws out. Error: The expression's value can not be retrieved. An error happened in data type conversion. Can not convert the value of org.eclipse.birt.data.engine.script.DataExceptionMocker@79c17b to Integer type.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/HighlightRuleBuilder.java
if ( expressionValue2 != null && ( !expressionValue2.isDisposed( ) ) )
				expressionValue2.setEnabled( val );
			if ( andLable != null && ( !andLable.isDisposed( ) ) )
			{
				andLable.setEnabled( val );
			}
		}
		else
		{
			setControlEnable( valueListComposite, val );
			if ( val )
			{
				checkAddButtonStatus( );
				checkEditDelButtonStatus( );
			}
		}
	}
	/**
	 * Gets if the expression field is not empty.
	 */
	private boolean isExpressionOK( )
	{
		if ( expression == null )
		{
			return false;
		}
		if ( expression.getText( ) == null
				|| expression.getText( ).length( ) == 0 )
		{
			return false;