diff --git a/applications/lazstats/LazStats.chm b/applications/lazstats/LazStats.chm
index 271cc2ae3..3f038bec4 100644
Binary files a/applications/lazstats/LazStats.chm and b/applications/lazstats/LazStats.chm differ
diff --git a/applications/lazstats/docs/HelpNDoc/LazStats.hnd b/applications/lazstats/docs/HelpNDoc/LazStats.hnd
index 89dacd432..001edc203 100644
Binary files a/applications/lazstats/docs/HelpNDoc/LazStats.hnd and b/applications/lazstats/docs/HelpNDoc/LazStats.hnd differ
diff --git a/applications/lazstats/source/LazStats.lpi b/applications/lazstats/source/LazStats.lpi
index 05aa81b7b..fcf29e470 100644
--- a/applications/lazstats/source/LazStats.lpi
+++ b/applications/lazstats/source/LazStats.lpi
@@ -1408,7 +1408,7 @@
     </CodeGeneration>
     <Linking>
       <Debugging>
-        <UseExternalDbgSyms Value="True"/>
+        <DebugInfoType Value="dsDwarf2"/>
       </Debugging>
       <LinkSmart Value="True"/>
       <Options>
@@ -1417,6 +1417,12 @@
         </Win32>
       </Options>
     </Linking>
+    <Other>
+      <CustomOptions Value="-dUSE_EXTERNAL_HELP_VIEWER"/>
+      <OtherDefines Count="1">
+        <Define0 Value="USE_EXTERNAL_HELP_VIEWER"/>
+      </OtherDefines>
+    </Other>
   </CompilerOptions>
   <Debugging>
     <Exceptions Count="7">
diff --git a/applications/lazstats/source/forms/help/helpunit.lfm b/applications/lazstats/source/forms/help/helpunit.lfm
index e05716680..c4aca36b2 100644
--- a/applications/lazstats/source/forms/help/helpunit.lfm
+++ b/applications/lazstats/source/forms/help/helpunit.lfm
@@ -59,14 +59,14 @@ object HelpFrm: THelpFrm
   object HTMLHelpDatabase1: THTMLHelpDatabase
     BaseURL = 'file://html/'
     AutoRegister = True
-    KeywordPrefix = 'HTML/'
-    left = 24
-    top = 24
+    KeywordPrefix = 'html/'
+    Left = 32
+    Top = 24
   end
   object HTMLBrowserHelpViewer1: THTMLBrowserHelpViewer
     BrowserParams = '%s'
     AutoRegister = True
-    left = 168
-    top = 24
+    Left = 168
+    Top = 24
   end
 end
diff --git a/applications/lazstats/source/forms/help/helpunit.pas b/applications/lazstats/source/forms/help/helpunit.pas
index b54cc3541..eecdfbacb 100644
--- a/applications/lazstats/source/forms/help/helpunit.pas
+++ b/applications/lazstats/source/forms/help/helpunit.pas
@@ -5,7 +5,7 @@ unit HelpUnit;
 interface
 
 uses
-  Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs,
+  Classes, SysUtils, {FileUtil, }LResources, Forms, Controls, Graphics, Dialogs,
   StdCtrls, LazHelpHTML, HelpIntfs;
 
 type
@@ -30,8 +30,44 @@ type
 var
   HelpFrm: THelpFrm;
 
+procedure ShowHelpTopic(AHelpContext: Word); overload;
+procedure ShowHelpTopic(AHelpID: PChar); overload;
+
 implementation
 
+uses
+  {$IFDEF USE_EXTERNAL_HELP_VIEWER}
+  {$IFDEF MSWINDOWS}
+  htmlhelp,
+  {$ENDIF}
+  {$ENDIF}
+  LazFileUtils;
+
+procedure ShowHelpTopic(AHelpContext: Word);
+var
+  fn: UnicodeString;
+begin
+ {$IFDEF USE_EXTERNAL_HELP_VIEWER}
+  {$IFDEF MSWINDOWS}
+  // see: http://www.helpware.net/download/delphi/hh_doc.txt
+  fn := UnicodeString(Application.HelpFile);
+  htmlhelp.HtmlHelpW(0, PWideChar(fn), HH_HELP_CONTEXT, AHelpContext);
+  {$ENDIF}
+ {$ENDIF}
+end;
+
+procedure ShowHelpTopic(AHelpID: PChar);
+var
+  topic: UnicodeString;
+begin
+  {$IFDEF USE_EXTERNAL_HELP_VIEWER}
+   {$IFDEF MSWINDOWS}
+   topic := UnicodeString(Application.HelpFile + '::/' + AHelpID);
+   htmlhelp.HtmlHelpW(0, PWideChar(topic), HH_DISPLAY_TOPIC, 0);
+   {$ENDIF}
+ {$ENDIF}
+end;
+
 { THelpFrm }
 
 procedure THelpFrm.FormShow(Sender: TObject);
@@ -45,8 +81,11 @@ begin
 end;
 
 procedure THelpFrm.HelpBtnClick(Sender: TObject);
+var
+  fn: String;
 begin
-  ShowHelpOrErrorForKeyword('','HTML/LAZTOC.html');
+  fn := Application.Location + 'html/LAZTOC.html';
+  ShowHelpOrErrorForKeyword('', SwitchPathDelims(fn, true)); //Application.Location + 'html/LAZTOC.html');
 end;
 
 initialization
diff --git a/applications/lazstats/source/forms/mainunit.lfm b/applications/lazstats/source/forms/mainunit.lfm
index c1db24e9f..db830f763 100644
--- a/applications/lazstats/source/forms/mainunit.lfm
+++ b/applications/lazstats/source/forms/mainunit.lfm
@@ -3,6 +3,8 @@ object OS3MainFrm: TOS3MainFrm
   Height = 519
   Top = 194
   Width = 725
+  HelpType = htKeyword
+  HelpKeyword = 'TableofContents.htm'
   Caption = 'LazStats'
   ClientHeight = 499
   ClientWidth = 725
@@ -234,8 +236,8 @@ object OS3MainFrm: TOS3MainFrm
     OnPrepareCanvas = DataGridPrepareCanvas
   end
   object MainMenu1: TMainMenu
-    left = 192
-    top = 200
+    Left = 192
+    Top = 200
     object MenuItem1: TMenuItem
       Caption = 'File'
       object NewFileBtn: TMenuItem
@@ -1050,22 +1052,23 @@ object OS3MainFrm: TOS3MainFrm
       object MenuItem46: TMenuItem
         Caption = '-'
       end
+      object mnuShowTOC: TMenuItem
+        Caption = 'Table of Contents'
+        HelpContext = 152
+        OnClick = mnuShowTOCClick
+      end
       object GridUse: TMenuItem
         Caption = 'Using the Grid'
         OnClick = GridUseClick
       end
-      object HelpContents: TMenuItem
-        Caption = 'General Help'
-        OnClick = HelpContentsClick
-      end
     end
   end
   object OpenDialog1: TOpenDialog
-    left = 312
-    top = 200
+    Left = 312
+    Top = 200
   end
   object SaveDialog1: TSaveDialog
-    left = 432
-    top = 200
+    Left = 432
+    Top = 200
   end
 end
diff --git a/applications/lazstats/source/forms/mainunit.pas b/applications/lazstats/source/forms/mainunit.pas
index 4a1b5204b..f987d76bc 100644
--- a/applications/lazstats/source/forms/mainunit.pas
+++ b/applications/lazstats/source/forms/mainunit.pas
@@ -7,18 +7,13 @@ unit MainUnit;
 
 {$mode objfpc}{$H+}
 
-{$DEFINE USE_EXTERNAL_HELP_VIEWER}
+//{$DEFINE USE_EXTERNAL_HELP_VIEWER}
 
 interface
 
 uses
   LCLType, Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics,
   Dialogs, Menus, ExtCtrls, StdCtrls, Grids,
- {$IFDEF USE_EXTERNAL_HELP_VIEWER}
-  {$IFDEF MSWINDOWS}
-  HtmlHelp,
-  {$ENDIF}
- {$ENDIF}
   Globals, DataProcs, DictionaryUnit;
 
 type
@@ -110,6 +105,7 @@ type
     MenuItem50: TMenuItem;
     MenuItem51: TMenuItem;
     MenuItem52: TMenuItem;
+    mnuShowTOC: TMenuItem;
     SimpChiSqr: TMenuItem;
     SRHItem: TMenuItem;
     OneCaseAnova: TMenuItem;
@@ -137,7 +133,6 @@ type
     pcontrochart: TMenuItem;
     OpenDialog1: TOpenDialog;
     SaveDialog1: TSaveDialog;
-    HelpContents: TMenuItem;
     InsNewCol: TMenuItem;
     CopyCol: TMenuItem;
     CutCol: TMenuItem;
@@ -282,8 +277,7 @@ type
     procedure CutColClick(Sender: TObject);
     procedure CutRowMenuClick(Sender: TObject);
     procedure DataGridClick(Sender: TObject);
-    procedure DataGridKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState
-      );
+    procedure DataGridKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
     procedure DataGridKeyPress(Sender: TObject; var Key: char);
     procedure DataGridPrepareCanvas(sender: TObject; aCol, aRow: Integer;
       aState: TGridDrawState);
@@ -303,7 +297,7 @@ type
     procedure GrdBkMnuClick(Sender: TObject);
     procedure GridUseClick(Sender: TObject);
     procedure GrpFreqClick(Sender: TObject);
-    procedure HelpContentsClick(Sender: TObject);
+    //procedure HelpContentsClick(Sender: TObject);
     procedure homotestClick(Sender: TObject);
     procedure HypergeoProbClick(Sender: TObject);
     procedure InsNewColClick(Sender: TObject);
@@ -379,6 +373,7 @@ type
     procedure MenuItem98Click(Sender: TObject);
     procedure MenuItem99Click(Sender: TObject);
     procedure MenuItem30Click(Sender: TObject);
+    procedure mnuShowTOCClick(Sender: TObject);
     procedure MultDistsClick(Sender: TObject);
     procedure MultXvsYClick(Sender: TObject);
     procedure NestedABCClick(Sender: TObject);
@@ -1339,6 +1334,9 @@ var
   ts: TTextStyle;
   justif: String;
 begin
+  if not (Sender = DataGrid) then
+    exit;
+
   ts := DataGrid.Canvas.TextStyle;
   justif := DictionaryFrm.DictGrid.Cells[7, aCol];
   if justif = '' then justif := 'L';
@@ -1589,27 +1587,17 @@ end;
 // Call HTML help (.chm file)
 function TOS3MainFrm.HelpHandler(Command: Word; Data: PtrInt;
   var CallHelp: Boolean): Boolean;
-var
-  topic: UnicodeString;
-  res: Integer;
-  fn: UnicodeString;
 begin
   if Command = HELP_CONTEXT then
-  begin
-    // see: http://www.helpware.net/download/delphi/hh_doc.txt
-    fn := UnicodeString(Application.HelpFile);
-    res := htmlhelp.HtmlHelpW(0, PWideChar(fn), HH_HELP_CONTEXT, Data);
-  end else
+    ShowHelpTopic(Data)
+  else
   if Command = HELP_COMMAND then
-  begin
-    topic := UnicodeString(Application.HelpFile + '::/' + {%H-}PChar(Data));
-    res := htmlhelp.HtmlHelpW(0, PWideChar(topic), HH_DISPLAY_TOPIC, 0);
-  end;
+    ShowHelpTopic({%H-}PChar(Data));
 
   // Don't call regular help
   CallHelp := False;
 
-  Result := res <> 0;
+  Result := true; //res <> 0;
 end;
 {$ENDIF}
 {$ENDIF}
@@ -1709,6 +1697,7 @@ begin
   GroupFreqForm.ShowModal;
 end;
 
+(*  replaced by ShowTOC
 // Menu "Help" > "General Help"
 procedure TOS3MainFrm.HelpContentsClick(Sender: TObject);
 begin
@@ -1716,7 +1705,7 @@ begin
     Application.CreateForm(THelpFrm, HelpFrm);
   HelpFrm.ShowModal;
 end;
-
+*)
 // Menu "Analyses" > "Brown-Forsythe test for homogeneity of variance"
 procedure TOS3MainFrm.homotestClick(Sender: TObject);
 Var
@@ -2029,9 +2018,15 @@ end;
 
 procedure TOS3MainFrm.MenuItem30Click(Sender: TObject);
 begin
-   RowColSwap;
+  RowColSwap;
 end;
 
+procedure TOS3MainFrm.mnuShowTOCClick(Sender: TObject);
+begin
+  ShowHelpTopic(mnuShowTOC.HelpContext);
+end;
+
+
 initialization
   {$I mainunit.lrs}
 
diff --git a/applications/lazstats/source/units/dataprocs.pas b/applications/lazstats/source/units/dataprocs.pas
index 5940e9565..648abfd2b 100644
--- a/applications/lazstats/source/units/dataprocs.pas
+++ b/applications/lazstats/source/units/dataprocs.pas
@@ -1627,12 +1627,12 @@ end;
 procedure RowColSwap;
 VAR
      i, j, Rows, Cols : integer;
-     tempgrid : StrDyneMat;
+     tempgrid : StrDyneMat = nil;
 begin
    Assert(OS3MainFrm <> nil);
    Assert(DictionaryFrm <> nil);
 
-     SetLength(tempgrid,NoCases+1,NoVariables+1);
+     SetLength(tempgrid ,NoCases+1,NoVariables+1);
      Rows := NoCases;
      Cols := NoVariables;
 
@@ -1803,7 +1803,8 @@ var
   i, j, k, NoStrings: integer;
   TempString: string;
   dup: boolean;
-  StrGrps, OneString : StrDyneVec;
+  StrGrps: StrdyneVec = nil;
+  OneString : StrDyneVec = nil;
   res: TModalResult;
 begin
   Result := true;