diff --git a/fine-poi/src/main/java/com/fr/third/v2/org/apache/poi/xssf/usermodel/XSSFSheet.java b/fine-poi/src/main/java/com/fr/third/v2/org/apache/poi/xssf/usermodel/XSSFSheet.java
index 750635c6d..6350f257f 100644
--- a/fine-poi/src/main/java/com/fr/third/v2/org/apache/poi/xssf/usermodel/XSSFSheet.java
+++ b/fine-poi/src/main/java/com/fr/third/v2/org/apache/poi/xssf/usermodel/XSSFSheet.java
@@ -174,6 +174,7 @@ public class XSSFSheet extends POIXMLDocumentPart implements Sheet  {
     private SortedMap<String,XSSFTable> tables;
     private List<CellRangeAddress> arrayFormulas;
     private XSSFDataValidationHelper dataValidationHelper;
+    private int size;
 
     /**
      * Creates new XSSFSheet   - called by XSSFWorkbook to create a sheet from scratch.
@@ -408,21 +409,13 @@ public class XSSFSheet extends POIXMLDocumentPart implements Sheet  {
             // throw IllegalStateException if the argument CellRangeAddress intersects with
             // a multi-cell array formula defined in this sheet
             validateArrayFormulas(region);
-
-            // Throw IllegalStateException if the argument CellRangeAddress intersects with
-            // a merged region already in this sheet
-            validateMergedRegions(region);
         }
 
         CTMergeCells ctMergeCells = worksheet.isSetMergeCells() ? worksheet.getMergeCells() : worksheet.addNewMergeCells();
         CTMergeCell ctMergeCell = ctMergeCells.addNewMergeCell();
         ctMergeCell.setRef(region.formatAsString());
-        final int numMergeRegions=ctMergeCells.sizeOfMergeCellArray();
-
-        // also adjust the number of merged regions overall
-        ctMergeCells.setCount(numMergeRegions);
 
-        return numMergeRegions-1;
+        return ++this.size;
     }
 
     /**