diff --git a/components/fpspreadsheet/examples/excel8demo/excel8write.lpr b/components/fpspreadsheet/examples/excel8demo/excel8write.lpr
index 30a18bfb6..247ddf4f9 100644
--- a/components/fpspreadsheet/examples/excel8demo/excel8write.lpr
+++ b/components/fpspreadsheet/examples/excel8demo/excel8write.lpr
@@ -11,7 +11,7 @@ program excel8write;
 
 uses
   Classes, SysUtils, fpspreadsheet, xlsbiff8,
-  laz_fpspreadsheet, fpsconvencoding;
+  laz_fpspreadsheet;
 
 const
   Str_First = 'First';
@@ -27,6 +27,7 @@ var
   MyRPNFormula: TsRPNFormula;
   MyDir: string;
   i: Integer;
+  lCell: PCell;
 begin
   MyDir := ExtractFilePath(ParamStr(0));
 
@@ -42,6 +43,12 @@ begin
   MyWorksheet.WriteUTF8Text(4, 2, Str_Total);// C5
   MyWorksheet.WriteNumber(4, 3, 10);        // D5
 
+  // D6 number with background color
+  MyWorksheet.WriteNumber(5, 3, 10);
+  lCell := MyWorksheet.GetCell(5,3);
+  lCell^.BackgroundColor := scPURPLE;
+  lCell^.UsedFormattingFields := [uffBackgroundColor];
+
 { Uncommend this to test large XLS files
   for i := 2 to 20 do
   begin
diff --git a/components/fpspreadsheet/fpsopendocument.pas b/components/fpspreadsheet/fpsopendocument.pas
index ab6b0cb7b..a6deebef9 100755
--- a/components/fpspreadsheet/fpsopendocument.pas
+++ b/components/fpspreadsheet/fpsopendocument.pas
@@ -81,7 +81,7 @@ type
       const AOverwriteExisting: Boolean = False); override;
     procedure WriteToStream(AStream: TStream; AData: TsWorkbook); override;
     { Record writing methods }
-    procedure WriteFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsFormula); override;
+    procedure WriteFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsFormula; ACell: PCell); override;
     procedure WriteLabel(AStream: TStream; const ARow, ACol: Word; const AValue: string; ACell: PCell); override;
     procedure WriteNumber(AStream: TStream; const ARow, ACol: Cardinal; const AValue: double; ACell: PCell); override;
   end;
@@ -639,7 +639,7 @@ begin
 end;
 
 procedure TsSpreadOpenDocWriter.WriteFormula(AStream: TStream; const ARow,
-  ACol: Word; const AFormula: TsFormula);
+  ACol: Word; const AFormula: TsFormula; ACell: PCell);
 begin
 {  // The row should already be the correct one
   FContent := FContent +
diff --git a/components/fpspreadsheet/fpspreadsheet.pas b/components/fpspreadsheet/fpspreadsheet.pas
index 811dc7e36..4970635ab 100755
--- a/components/fpspreadsheet/fpspreadsheet.pas
+++ b/components/fpspreadsheet/fpspreadsheet.pas
@@ -330,8 +330,8 @@ type
       const AOverwriteExisting: Boolean = False); virtual;
     procedure WriteToStream(AStream: TStream; AData: TsWorkbook); virtual;
     { Record writing methods }
-    procedure WriteFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsFormula); virtual;
-    procedure WriteRPNFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsRPNFormula); virtual;
+    procedure WriteFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsFormula; ACell: PCell); virtual;
+    procedure WriteRPNFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsRPNFormula; ACell: PCell); virtual;
     procedure WriteLabel(AStream: TStream; const ARow, ACol: Word; const AValue: string; ACell: PCell); virtual; abstract;
     procedure WriteNumber(AStream: TStream; const ARow, ACol: Cardinal; const AValue: double; ACell: PCell); virtual; abstract;
   end;
@@ -1430,10 +1430,10 @@ end;
 procedure TsCustomSpreadWriter.WriteCellCallback(ACell: PCell; AStream: TStream);
 begin
   case ACell.ContentType of
-    cctNumber:  WriteNumber(AStream, ACell^.Row, ACell^.Col, ACell^.NumberValue, ACell);
-    cctUTF8String:  WriteLabel(AStream, ACell^.Row, ACell^.Col, ACell^.UTF8StringValue, ACell);
-    cctFormula: WriteFormula(AStream, ACell^.Row, ACell^.Col, ACell^.FormulaValue);
-    cctRPNFormula: WriteRPNFormula(AStream, ACell^.Row, ACell^.Col, ACell^.RPNFormulaValue);
+    cctNumber:     WriteNumber(AStream, ACell^.Row, ACell^.Col, ACell^.NumberValue, ACell);
+    cctUTF8String: WriteLabel(AStream, ACell^.Row, ACell^.Col, ACell^.UTF8StringValue, ACell);
+    cctFormula:    WriteFormula(AStream, ACell^.Row, ACell^.Col, ACell^.FormulaValue, ACell);
+    cctRPNFormula: WriteRPNFormula(AStream, ACell^.Row, ACell^.Col, ACell^.RPNFormulaValue, ACell);
   end;
 end;
 
@@ -1508,13 +1508,13 @@ begin
 end;
 
 procedure TsCustomSpreadWriter.WriteFormula(AStream: TStream; const ARow,
-  ACol: Word; const AFormula: TsFormula);
+  ACol: Word; const AFormula: TsFormula; ACell: PCell);
 begin
 
 end;
 
 procedure TsCustomSpreadWriter.WriteRPNFormula(AStream: TStream; const ARow,
-  ACol: Word; const AFormula: TsRPNFormula);
+  ACol: Word; const AFormula: TsRPNFormula; ACell: PCell);
 begin
 
 end;
diff --git a/components/fpspreadsheet/xlsbiff2.pas b/components/fpspreadsheet/xlsbiff2.pas
index 0ec03daff..0dfbb25fc 100755
--- a/components/fpspreadsheet/xlsbiff2.pas
+++ b/components/fpspreadsheet/xlsbiff2.pas
@@ -66,7 +66,7 @@ type
     { Record writing methods }
     procedure WriteBOF(AStream: TStream);
     procedure WriteEOF(AStream: TStream);
-    procedure WriteRPNFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsRPNFormula); override;
+    procedure WriteRPNFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsRPNFormula; ACell: PCell); override;
     procedure WriteLabel(AStream: TStream; const ARow, ACol: Word; const AValue: string; ACell: PCell); override;
     procedure WriteNumber(AStream: TStream; const ARow, ACol: Cardinal; const AValue: double; ACell: PCell); override;
   end;
@@ -219,7 +219,7 @@ end;
   MyFormula[2].TokenID := INT_EXCEL_TOKEN_TADD;  +
 }
 procedure TsSpreadBIFF2Writer.WriteRPNFormula(AStream: TStream; const ARow,
-  ACol: Word; const AFormula: TsRPNFormula);
+  ACol: Word; const AFormula: TsRPNFormula; ACell: PCell);
 var
   FormulaResult: double;
   i: Integer;
diff --git a/components/fpspreadsheet/xlsbiff5.pas b/components/fpspreadsheet/xlsbiff5.pas
index b59fee4d9..5d699a254 100755
--- a/components/fpspreadsheet/xlsbiff5.pas
+++ b/components/fpspreadsheet/xlsbiff5.pas
@@ -121,7 +121,7 @@ type
     procedure WriteDimensions(AStream: TStream; AWorksheet: TsWorksheet);
     procedure WriteEOF(AStream: TStream);
     procedure WriteFont(AStream: TStream;  AFont: TFPCustomFont);
-    procedure WriteRPNFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsRPNFormula); override;
+    procedure WriteRPNFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsRPNFormula; ACell: PCell); override;
     procedure WriteIndex(AStream: TStream);
     procedure WriteLabel(AStream: TStream; const ARow, ACol: Word; const AValue: string; ACell: PCell); override;
     procedure WriteNumber(AStream: TStream; const ARow, ACol: Cardinal; const AValue: double; ACell: PCell); override;
@@ -628,7 +628,7 @@ end;
 *
 *******************************************************************}
 procedure TsSpreadBIFF5Writer.WriteRPNFormula(AStream: TStream; const ARow,
-  ACol: Word; const AFormula: TsRPNFormula);
+  ACol: Word; const AFormula: TsRPNFormula; ACell: PCell);
 var
   FormulaResult: double;
   i: Integer;
diff --git a/components/fpspreadsheet/xlsbiff8.pas b/components/fpspreadsheet/xlsbiff8.pas
index f7fcbb606..19280ad59 100755
--- a/components/fpspreadsheet/xlsbiff8.pas
+++ b/components/fpspreadsheet/xlsbiff8.pas
@@ -143,8 +143,8 @@ type
     procedure WriteDimensions(AStream: TStream; AWorksheet: TsWorksheet);
     procedure WriteEOF(AStream: TStream);
     procedure WriteFont(AStream: TStream; AFont: TFPCustomFont);
-    procedure WriteFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsFormula); override;
-    procedure WriteRPNFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsRPNFormula); override;
+    procedure WriteFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsFormula; ACell: PCell); override;
+    procedure WriteRPNFormula(AStream: TStream; const ARow, ACol: Word; const AFormula: TsRPNFormula; ACell: PCell); override;
     procedure WriteIndex(AStream: TStream);
     procedure WriteLabel(AStream: TStream; const ARow, ACol: Word; const AValue: string; ACell: PCell); override;
     procedure WriteNumber(AStream: TStream; const ARow, ACol: Cardinal; const AValue: double; ACell: PCell); override;
@@ -755,7 +755,7 @@ end;
 *
 *******************************************************************}
 procedure TsSpreadBIFF8Writer.WriteFormula(AStream: TStream; const ARow,
-  ACol: Word; const AFormula: TsFormula);
+  ACol: Word; const AFormula: TsFormula; ACell: PCell);
 {var
   FormulaResult: double;
   i: Integer;
@@ -835,7 +835,7 @@ begin
 end;
 
 procedure TsSpreadBIFF8Writer.WriteRPNFormula(AStream: TStream; const ARow,
-  ACol: Word; const AFormula: TsRPNFormula);
+  ACol: Word; const AFormula: TsRPNFormula; ACell: PCell);
 var
   FormulaResult: double;
   i: Integer;
@@ -855,8 +855,9 @@ begin
   AStream.WriteWord(WordToLE(ARow));
   AStream.WriteWord(WordToLE(ACol));
 
-  { Index to XF Record }
-  AStream.WriteWord($0000);
+  { Index to XF record, according to formatting }
+  //AStream.WriteWord(0);
+  WriteXFIndex(AStream, ACell);
 
   { Result of the formula in IEE 754 floating-point value }
   AStream.WriteBuffer(FormulaResult, 8);
@@ -1040,8 +1041,8 @@ begin
   AStream.WriteWord(WordToLE(ARow));
   AStream.WriteWord(WordToLE(ACol));
 
-  { Index to XF record }
-  AStream.WriteWord(WordToLE($0));
+  { Index to XF record, according to formatting }
+  WriteXFIndex(AStream, ACell);
 
   { IEE 754 floating-point value (is different in BIGENDIAN???) }
   AStream.WriteBuffer(AValue, 8);