diff --git a/components/fpspreadsheet/fpspreadsheet.pas b/components/fpspreadsheet/fpspreadsheet.pas
index d5efc670e..d54e8e34b 100755
--- a/components/fpspreadsheet/fpspreadsheet.pas
+++ b/components/fpspreadsheet/fpspreadsheet.pas
@@ -409,6 +409,7 @@ type
     function  GetLastRowNumber: Cardinal; deprecated 'Use GetLastRowIndex';
 
     { Data manipulation methods - For Rows and Cols }
+    function  AddRow(ARow: Cardinal): PRow;
     function  CalcAutoRowHeight(ARow: Cardinal): Single;
     function  CalcRowHeight(ARow: Cardinal): Single;
     function  FindRow(ARow: Cardinal): PRow;
@@ -6399,16 +6400,27 @@ end;
 function TsWorksheet.GetRow(ARow: Cardinal): PRow;
 begin
   Result := FindRow(ARow);
-  if (Result = nil) then begin
-    Result := GetMem(SizeOf(TRow));
-    FillChar(Result^, SizeOf(TRow), #0);
-    Result^.Row := ARow;
-    FRows.Add(Result);
-    if FLastRowIndex = 0 then
-      FLastRowIndex := GetLastRowIndex(true)
-    else
-      FLastRowIndex := Max(FLastRowIndex, ARow);
-  end;
+  if (Result = nil) then
+    Result := AddRow(ARow);
+end;
+
+{@@ ----------------------------------------------------------------------------
+ Creates a new row record for the specific row index. It is not checked whether
+ a row record already exists for this index. Dupliate records must be avoided!
+
+ @param  ARow   Index of the row considered
+ @return        Pointer to the row record with this row index.
+-------------------------------------------------------------------------------}
+function TsWorksheet.AddRow(ARow: Cardinal): PRow;
+begin
+  Result := GetMem(SizeOf(TRow));
+  FillChar(Result^, SizeOf(TRow), #0);
+  Result^.Row := ARow;
+  FRows.Add(Result);
+  if FLastRowIndex = 0 then
+    FLastRowIndex := GetLastRowIndex(true)
+  else
+    FLastRowIndex := Max(FLastRowIndex, ARow);
 end;
 
 {@@ ----------------------------------------------------------------------------
diff --git a/components/fpspreadsheet/fpspreadsheetctrls.pas b/components/fpspreadsheet/fpspreadsheetctrls.pas
index 2e4cd5ef4..e1a3c8a85 100644
--- a/components/fpspreadsheet/fpspreadsheetctrls.pas
+++ b/components/fpspreadsheet/fpspreadsheetctrls.pas
@@ -64,7 +64,7 @@ type
     FUserFileFormatID: TsSpreadFormatID;
     FPendingSelection: TsCellRangeArray;
     FPendingOperation: TsCopyOperation;
-    FControlLockCount: Integer;
+//    FControlLockCount: Integer;
     FOptions: TsWorkbookOptions;
     FOnError: TsWorkbookSourceErrorEvent;
 
@@ -128,8 +128,8 @@ type
     procedure SaveToSpreadsheetFile(AFileName: string; AFormatID: TsSpreadFormatID;
       AOverwriteExisting: Boolean = true); overload;
 
-    procedure DisableControls;
-    procedure EnableControls;
+//    procedure DisableControls;
+//    procedure EnableControls;
 
     procedure SelectCell(ASheetRow, ASheetCol: Cardinal);
     procedure SelectWorksheet(AWorkSheet: TsWorksheet);
@@ -779,14 +779,14 @@ begin
   FWorksheet := FWorkbook.AddWorksheet(Format(rsDefaultSheetName,[1]));
   SelectWorksheet(FWorksheet);
 end;
-
+                         (*
 {@@ ----------------------------------------------------------------------------
   Disables notification of listening controls
 -------------------------------------------------------------------------------}
 procedure TsWorkbookSource.DisableControls;
 begin
   inc(FControlLockCount);
-end;
+end;                   *)
 
 {@@ ----------------------------------------------------------------------------
   An error has occured during loading of the workbook. Shows a message box by
@@ -804,14 +804,14 @@ begin
   else
     MessageDlg(AErrorMsg, mtError, [mbOK], 0);
 end;
-
+                   (*
 {@@ ----------------------------------------------------------------------------
   Enables notification of listening controls
 -------------------------------------------------------------------------------}
 procedure TsWorkbookSource.EnableControls;
 begin
   dec(FControlLockCount);
-end;
+end;                 *)
 
 {@@ ----------------------------------------------------------------------------
   Executes a "pending operation"
@@ -969,12 +969,13 @@ begin
       book.ReadFromFile(AFileName, AFormatID);
   except
     book.AddErrorMsg(rsCannotReadFile, [AFileName]);
-    // Code executed subsequently will be a pain if there is no worksheet!
+    // Code executed subsequently will be a pain if there is no worksheet! --> Add one.
     if book.GetWorksheetCount = 0 then
       book.AddWorksheet(Format(rsDefaultSheetName, [1]));
   end;
 
   InternalLoadFromWorkbook(book, AWorksheetIndex);
+
   (*
 
 
@@ -1016,6 +1017,8 @@ end;
 procedure TsWorkbookSource.InternalLoadFromWorkbook(AWorkbook: TsWorkbook;
   AWorksheetIndex: Integer = -1);
 begin
+  AWorkbook.DisableNotifications;
+
   InternalCreateNewWorkbook(AWorkbook);
   WorkbookOpenedHandler(self);
 
@@ -1027,6 +1030,8 @@ begin
   end;
   SelectWorksheet(FWorkbook.GetWorksheetByIndex(AWorksheetIndex));
 
+  AWorkbook.EnableNotifications;
+
   // If required, display loading error message
   if FWorkbook.ErrorMsg <> '' then
     DoShowError(FWorkbook.ErrorMsg);
diff --git a/components/fpspreadsheet/fpspreadsheetgrid.pas b/components/fpspreadsheet/fpspreadsheetgrid.pas
index 19c9938d4..5ed5b92a9 100644
--- a/components/fpspreadsheet/fpspreadsheetgrid.pas
+++ b/components/fpspreadsheet/fpspreadsheetgrid.pas
@@ -966,6 +966,9 @@ begin
 end;
 
 
+{*******************************************************************************
+*                                   TsSelPen                                   *
+*******************************************************************************}
 constructor TsSelPen.Create;
 begin
   inherited;
@@ -973,6 +976,7 @@ begin
   JoinStyle := pjsMiter;
 end;
 
+
 {*******************************************************************************
 *                              TsCustomWorksheetGrid                           *
 *******************************************************************************}
@@ -4475,6 +4479,7 @@ begin
     //Avoid crash when accessing the canvas, e.g. in GetDefaultHeaderColWidth
     exit;
    }
+
   if (Worksheet = nil) or (Worksheet.GetCellCount = 0) then begin
     FixedCols := FFrozenCols + FHeaderCount;
     FixedRows := FFrozenRows + FHeaderCount;
@@ -4824,13 +4829,15 @@ procedure TsCustomWorksheetGrid.UpdateRowHeight(ARow: Integer;
   AEnforceCalcRowHeight: Boolean = false);
 var
   lRow: PRow;
+  sr: Cardinal;
   h: Integer;     // Row height, in pixels. Contains zoom factor.
   doCalcRowHeight: Boolean;
 begin
   h := 0;
   if Worksheet <> nil then
   begin
-    lRow := Worksheet.FindRow(ARow - FHeaderCount);
+    sr := ARow - FHeaderCount;    // worksheet row index
+    lRow := Worksheet.FindRow(sr);
     if (lRow <> nil) then begin
       case lRow^.RowHeightType of
         rhtCustom:
@@ -4856,11 +4863,13 @@ begin
       end;  // case
     end else
     // No row record so far.
-    if Worksheet.GetCellCountInRow(ARow - FHeaderCount) > 0 then
+    if Worksheet.GetCellCountInRow(sr) > 0 then
     begin
       // Case 1: This row does contain cells
-      lRow := Worksheet.GetRow(ARow - FHeaderCount);
-      h := CalcAutoRowHeight(ARow);
+      lRow := Worksheet.AddRow(sr);
+      if AEnforceCalcRowHeight then
+        h := CalcAutoRowHeight(ARow) else
+        h := DefaultRowHeight;
       lRow^.Height := CalcRowHeightToSheet(round(h / ZoomFactor));
       if h <> DefaultRowHeight then
         lRow^.RowHeightType := rhtAuto
@@ -5972,8 +5981,12 @@ end;
 procedure TsCustomWorksheetGrid.SetZoomFactor(AValue: Double);
 begin
   if (AValue <> GetZoomFactor) and Assigned(Worksheet) then begin
-    Worksheet.ZoomFactor := abs(AValue);
-    AdaptToZoomFactor;
+    try
+      Worksheet.ZoomFactor := abs(AValue);
+      AdaptToZoomFactor;
+    finally
+      EndUpdate;
+    end;
   end;
 end;