diff --git a/components/fpspreadsheet/source/common/fpsexprparser.pas b/components/fpspreadsheet/source/common/fpsexprparser.pas
index e82a85211..e88179648 100644
--- a/components/fpspreadsheet/source/common/fpsexprparser.pas
+++ b/components/fpspreadsheet/source/common/fpsexprparser.pas
@@ -3991,16 +3991,55 @@ end;
 constructor TsCellRangeExprNode.Create(AParser: TsExpressionParser;
   AWorksheet: TsWorksheet; ASheet1, ASheet2: String;
   ARow1, ACol1, ARow2, ACol2: Cardinal; AFlags: tsRelFlags; Is3DRange: Boolean);
+var
+  tmp: Integer;
 begin
   FParser := AParser;
   FWorksheet := AWorksheet;
+  FFlags := [];
+
+  if (ASheet1 = '') and (ASheet2 <> '') then
+    raise Exception.Create('Invalid parameters in cell range');
+
   FSheet[1] := GetWorkbook.GetWorksheetIndex(ASheet1);
-  if ASheet2 = '' then FSheet[2] := FSheet[1] else FSheet[2] := GetWorkbook.GetWorksheetIndex(ASheet2);
-  FRow[1] := ARow1;
-  FCol[1] := ACol1;
-  if ARow2 = Cardinal(-1) then FRow[2] := FRow[1] else FRow[2] := ARow2;
-  if ACol2 = Cardinal(-1) then FCol[2] := FCol[1] else FCol[2] := ACol2;
-  FFlags := AFlags;
+  if ASheet2 <> '' then
+    FSheet[2] := GetWorkbook.GetWorksheetIndex(ASheet2)
+  else
+    FSheet[2] := FSheet[1];
+  EnsureOrder(FSheet[1], FSheet[2]);
+
+  if ARow2 = Cardinal(-1) then
+    ARow2 := ARow1;
+  if ARow1 <= ARow2 then
+  begin
+    FRow[1] := ARow1;
+    FRow[2] := ARow2;
+    FCol[1] := ACol1;
+    if rfRelRow in AFlags then Include(FFlags, rfRelRow);
+    if rfRelRow2 in AFlags then Include(FFlags, rfRelRow2);
+  end else
+  begin
+    FRow[1] := ARow2;
+    FRow[2] := ARow1;
+    if rfRelRow in AFlags then Include(FFlags, rfRelRow2);
+    if rfRelRow2 in AFlags then Include(FFlags, rfRelRow);
+  end;
+
+  if ACol2 = Cardinal(-1) then
+    ACol2 := ACol1;
+  if ACol1 <= ACol2 then
+  begin
+    FCol[1] := ACol1;
+    FCol[2] := ACol2;
+    if (rfRelCol in AFlags) then Include(FFlags, rfRelCol);
+    if (rfRelCol2 in AFlags) then Include(FFlags, rfRelCol2);
+  end else
+  begin
+    FCol[1] := ACol2;
+    FCol[2] := ACol1;
+    if (rfRelCol in AFlags) then Include(FFlags, rfRelCol2);
+    if (rfRelCol2 in AFlags) then Include(FFlags, rfRelCol);
+  end;
   F3dRange := Is3dRange;
 end;
 
diff --git a/components/fpspreadsheet/source/common/fpspreadsheet.pas b/components/fpspreadsheet/source/common/fpspreadsheet.pas
index 5795befaf..04680dc0e 100644
--- a/components/fpspreadsheet/source/common/fpspreadsheet.pas
+++ b/components/fpspreadsheet/source/common/fpspreadsheet.pas
@@ -5731,12 +5731,12 @@ begin
 
     parser := TsSpreadsheetParser.Create(self);
     try
-      if ALocalized then begin
+      if ALocalized then
         // Convert "localized" formula to standard format
-        parser.LocalizedExpression[Workbook.FormatSettings] := AFormula;
-        AFormula := parser.Expression;
-      end else
+        parser.LocalizedExpression[Workbook.FormatSettings] := AFormula
+      else
         parser.Expression := AFormula;
+      AFormula := parser.Expression;
       if parser.Has3DLinks
         then ACell.Flags := ACell.Flags + [cf3dFormula]
         else ACell.Flags := ACell.Flags - [cf3dFormula];
diff --git a/components/fpspreadsheet/tests/singleformulatests.pas b/components/fpspreadsheet/tests/singleformulatests.pas
index 85dbcfa6e..446a3dc87 100644
--- a/components/fpspreadsheet/tests/singleformulatests.pas
+++ b/components/fpspreadsheet/tests/singleformulatests.pas
@@ -23,7 +23,8 @@ type
     procedure SetUp; override;
     procedure TearDown; override;
     procedure TestFloatFormula(AFormula: String; AExpected: Double;
-      ATestKind: TFormulaTestKind; AFormat: TsSpreadsheetFormat);
+      ATestKind: TFormulaTestKind; AFormat: TsSpreadsheetFormat;
+      AExpectedFormula: String = '');
 
   published
     procedure AddConst_BIFF2;
@@ -54,6 +55,10 @@ type
     procedure SumMultiSheetRange_OOXML;
     procedure SumMultiSheetRange_ODS;
 
+    procedure SumMultiSheetRange_FlippedCells_OOXML;
+    procedure SumMultiSheetRange_FlippedSheets_OOXML;
+    procedure SumMultiSheetRange_FlippedSheetsAndCells_OOXML;
+
   end;
 
 implementation
@@ -78,7 +83,8 @@ begin
 end;
 
 procedure TSpreadSingleFormulaTests.TestFloatFormula(AFormula: String;
-  AExpected: Double; ATestKind: TFormulaTestKind; AFormat: TsSpreadsheetFormat);
+  AExpected: Double; ATestKind: TFormulaTestKind; AFormat: TsSpreadsheetFormat;
+  AExpectedFormula: String = '');
 const
   SHEET1 = 'Sheet1';
   SHEET2 = 'Sheet2';
@@ -95,6 +101,7 @@ var
   actualValue: Double;
 begin
   TempFile := GetTempFileName;
+  if AExpectedFormula = '' then AExpectedFormula := AFormula;
 
   try
     // Create test workbook and write test formula and needed cells
@@ -132,7 +139,7 @@ begin
 
       // Read formula before saving
       actualFormula := cell^.Formulavalue;
-      CheckEquals(AFormula, actualFormula, 'Unsaved formula text mismatch');
+      CheckEquals(AExpectedFormula, actualFormula, 'Unsaved formula text mismatch');
 
       // Read calculated value before saving
       actualvalue := worksheet.ReadAsNumber(TESTCELL_ROW, TESTCELL_COL);
@@ -157,7 +164,7 @@ begin
 
       cell := worksheet.FindCell(TESTCELL_ROW, TESTCELL_COL);
       actualformula := cell^.FormulaValue;
-      CheckEquals(AFormula, actualformula, 'Saved formula text mismatch.');
+      CheckEquals(AExpectedFormula, actualformula, 'Saved formula text mismatch.');
     finally
       workbook.Free;
     end;
@@ -290,6 +297,23 @@ begin
   TestFloatFormula('SUM(Sheet2:Sheet3!C3:C5)', 55.0, ftkCellRangeSheetRange, sfOpenDocument);
 end;
 
+{ --- }
+
+procedure TSpreadSingleFormulaTests.SumMultiSheetRange_FlippedSheetsAndCells_OOXML;
+begin
+  TestFloatFormula('SUM(Sheet3:Sheet2!C5:C3)', 55.0, ftkCellRangeSheetRange, sfOOXML, 'SUM(Sheet2:Sheet3!C3:C5)');
+end;
+
+procedure TSpreadSingleFormulaTests.SumMultiSheetRange_FlippedCells_OOXML;
+begin
+  TestFloatFormula('SUM(Sheet2:Sheet3!C5:C3)', 55.0, ftkCellRangeSheetRange, sfOOXML, 'SUM(Sheet2:Sheet3!C3:C5)');
+end;
+
+procedure TSpreadSingleFormulaTests.SumMultiSheetRange_FlippedSheets_OOXML;
+begin
+  TestFloatFormula('SUM(Sheet3:Sheet2!C3:C5)', 55.0, ftkCellRangeSheetRange, sfOOXML, 'SUM(Sheet2:Sheet3!C3:C5)');
+end;
+
 initialization
   // Register to include these tests in a full run
   RegisterTest(TSpreadSingleFormulaTests);