diff --git a/src/include/msksheet.cpp b/src/include/msksheet.cpp
index e45f1543c..e79c3d43d 100755
--- a/src/include/msksheet.cpp
+++ b/src/include/msksheet.cpp
@@ -858,6 +858,11 @@ void TSpreadsheet::update_original_rows(int r)
 		_original_str = _str;
 	else
 	{
+		if (_original_str.rowptr(r) == nullptr)
+			_original_str.add(new TToken_string, r);
+		if (_str.rowptr(r) == nullptr)
+			_str.add(new TToken_string, r);
+
 		TToken_string & original_row = _original_str.row(r);
 		TToken_string & row = _str.row(r);