Reproducing Steps:

1. run the test case zss.test \ org.zkoss.zss.model.importer.ExcelImporterTest

failed on [Export XLS] D:\git\zkspreadsheet\zss.test\src\test\java\org\zkoss\zss\api\impl\book\280-reapply.xlsx
java.lang.RuntimeException : No external workbook with name '1'
at org.zkoss.poi.hssf.model.LinkTable.getExternalSheetIndex( LinkTable.java:393)
at org.zkoss.poi.hssf.model.InternalWorkbook.getExternalSheetIndex( InternalWorkbook.java:1897)
at org.zkoss.poi.hssf.usermodel.HSSFEvaluationWorkbook.getExternalSheetIndex( HSSFEvaluationWorkbook.java:72)
at org.zkoss.poi.ss.formula.FormulaParser.createAreaRefParseNode( FormulaParser.java:655)
at org.zkoss.poi.ss.formula.FormulaParser.parseRangeable( FormulaParser.java:529)
at org.zkoss.poi.ss.formula.FormulaParser.parseRangeExpression( FormulaParser.java:285)
at org.zkoss.poi.ss.formula.FormulaParser.parseSimpleFactor( FormulaParser.java:1163)
at org.zkoss.poi.ss.formula.FormulaParser.percentFactor( FormulaParser.java:1123)
at org.zkoss.poi.ss.formula.FormulaParser.powerFactor( FormulaParser.java:1110)
at org.zkoss.poi.ss.formula.FormulaParser.Term(FormulaParser.java:1470 )
at org.zkoss.poi.ss.formula.FormulaParser.additiveExpression( FormulaParser.java:1570)
at org.zkoss.poi.ss.formula.FormulaParser.concatExpression( FormulaParser.java:1554)
at org.zkoss.poi.ss.formula.FormulaParser.comparisonExpression( FormulaParser.java:1511)
at org.zkoss.poi.ss.formula.FormulaParser.unionExpression( FormulaParser.java:1491)
at org.zkoss.poi.ss.formula.FormulaParser.parse(FormulaParser.java:1612 )
at org.zkoss.poi.ss.formula.FormulaParser.parse(FormulaParser.java:193 )
at org.zkoss.poi.hssf.model.HSSFFormulaParser.parse( HSSFFormulaParser.java:72)
at org.zkoss.poi.hssf.usermodel.HSSFName.setRefersToFormula( HSSFName.java:187)
at org.zkoss.zss.range.impl.imexp.AbstractExcelExporter.exportNamedRange( AbstractExcelExporter.java:115)
at org.zkoss.zss.range.impl.imexp.AbstractExcelExporter.export( AbstractExcelExporter.java:86)
at org.zkoss.zss.range.impl.imexp.AbstractExporter.export( AbstractExporter.java:37)
at org.zkoss.zss.model.importer.ExcelImporterTest.importExport( ExcelImporterTest.java:66)
at sun.reflect.NativeMethodAccessorImpl.invoke0( Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39 )
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25 )
at java.lang.reflect.Method.invoke( Method.java:597 )
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall( FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run( ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively( FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate( InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271 )
at org.junit.runners.BlockJUnit4ClassRunner.runChild( BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild( BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238 )
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63 )
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236 )
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53 )
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229 )
at org.junit.runners.ParentRunner.run(ParentRunner.java:309 )
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run( JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run( TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests( RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests( RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run( RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main( RemoteTestRunner.java:197)