Fix unable to set mutiple print area in HSSF

main/SS/Formula/OperandClassTransformer.cs

@@ -114,11 +114,21 @@ private void TransformNode(ParseNode node, byte desiredOperandClass,
             // Note - the tAttrSum token (node.getToken()) is a base
             // token so does not need to have its operand class set
         }
-            if (token is ValueOperatorPtg || token is ControlPtg
-                || token is MemFuncPtg
+            if (token is MemFuncPtg
                 || token is MemAreaPtg
                 || token is UnionPtg
                 || token is IntersectionPtg)
+            {
+                // Reference-type operators: children preserve the desired operand class.
+                // This ensures that Area3DPtg tokens inside union/intersection expressions
+                // (e.g. multiple print areas) keep CLASS_REF when used in a named range context.
+                for (int i = 0; i < children.Length; i++)
+                {
+                    TransformNode(children[i], desiredOperandClass, callerForceArrayFlag);
+                }
+                return;
+            }
+            if (token is ValueOperatorPtg || token is ControlPtg)
             {
                 // Value Operator Ptgs and Control are base Tokens, so Token will be unchanged
                 // but any child nodes are processed according To desiredOperandClass and callerForceArrayFlag

testcases/main/SS/UserModel/BaseTestWorkbook.cs

@@ -388,6 +388,28 @@ public void TestPrintArea()
             workbook.Close();
         }
 
+        [Test]
+        public void TestMultiplePrintArea()
+        {
+            IWorkbook workbook = _testDataProvider.CreateWorkbook();
+            ISheet sheet1 = workbook.CreateSheet("Sheet1");
+            String sheetName1 = sheet1.SheetName;
+
+            // Set multiple print areas with comma-delimited references
+            String reference = "$A$1:$C$5,$E$6:$F$9";
+            workbook.SetPrintArea(0, reference);
+            String retrievedPrintArea = workbook.GetPrintArea(0);
+            ClassicAssert.IsNotNull(retrievedPrintArea, "Multiple print area should not be null");
+            // Both areas should be present with the sheet name prefix
+            ClassicAssert.IsTrue(retrievedPrintArea.Contains("$A$1:$C$5"), "First area should be present");
+            ClassicAssert.IsTrue(retrievedPrintArea.Contains("$E$6:$F$9"), "Second area should be present");
+            ClassicAssert.IsTrue(retrievedPrintArea.Contains(sheetName1), "Sheet name should be present");
+
+            workbook.RemovePrintArea(0);
+            ClassicAssert.IsNull(workbook.GetPrintArea(0));
+            workbook.Close();
+        }
+
         [Test]
         public void TestGetSetActiveSheet()
         {