--- org/apache/poi/hssf/model/Sheet.java	Sat Jun 21 13:51:18 2008
+++ org/apache/poi/hssf/model/Sheet.java	Wed Jul 16 16:21:09 2008
@@ -827,16 +827,18 @@ 
 
             // If the BOF record was just serialized then add the IndexRecord
             if (record.getSid() == BOFRecord.sid) {
-              // Add an optional UncalcedRecord
-              if (_isUncalced) {
-                  UncalcedRecord rec = new UncalcedRecord();
-                  pos += rec.serialize(pos, data);
-              }
-              //Can there be more than one BOF for a sheet? If not then we can
-              //remove this guard. So be safe it is left here.
-              if (rows != null && !haveSerializedIndex) {
+              if (!haveSerializedIndex) {
                 haveSerializedIndex = true;
-                pos += serializeIndexRecord(k, pos, data);
+                // Add an optional UncalcedRecord - for size calculation we have to be shure to add it only once (each diagrams have new BOFRecord)
+                if (_isUncalced) {
+                    UncalcedRecord rec = new UncalcedRecord();
+                    pos += rec.serialize(pos, data);
+                }
+                //Can there be more than one BOF for a sheet? If not then we can
+                //remove this guard. So be safe it is left here.
+                if (rows != null) {
+                  pos += serializeIndexRecord(k, pos, data);
+                }
               }
             }
         }