get all opened internet explorer windows

I want to get all opened internet explorer windows and add the window's caption to a ListBox.
i don't want the program to unselect the selected item in the listbox when it gets updated by the timer, so it does a for-loop and checks if the content in the stringlist (IEWndsList) has been changed, if so, then it puts the content in the listbox.

i use the following code:
unit Main;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Menus, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    PopupMenu1: TPopupMenu;
    ListBox1: TListBox;
    Closewindow1: TMenuItem;
    Timer1: TTimer;
    procedure Closewindow1Click(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  IEWndsList: TStringList;
  index: integer;

implementation

{$R *.dfm}

function EnumIEWndsProc(hWnd, lParam: Integer): Boolean; stdcall;
var Cap: PChar;
    Len: Integer;
    cn: array[0..7] of Char;
begin
 Result := True;
 GetClassName(hWnd, cn, 8);
 if cn = 'IEFrame' then begin
   Len := GetWindowTextLength(hWnd) + 1;
   GetMem(Cap, Len);
   GetWindowText(hWnd, Cap, Len);
   IEWndsList.Add(Cap);
   FreeMem(Cap);
 end;
end;

procedure SetHorizontalScroll(alb: TListBox);
var i, len, lbsw: integer;
begin
lbsw := 0;
 with alb do begin
  for i := 0 to Items.Count - 1 do begin
   len := Canvas.TextWidth(Items[i]);
   if len > lbsw then lbsw := len;
  end;
  Perform(LB_SETHORIZONTALEXTENT, lbsw + 7, 0);
 end;
end;

procedure TForm1.Closewindow1Click(Sender: TObject);
begin
 if ListBox1.ItemIndex <> -1 then SendMessage(FindWindow(nil, PChar(ListBox1.Items.Strings[ListBox1.ItemIndex])), WM_SYSCOMMAND, SC_CLOSE, 0);
end;

procedure TForm1.Timer1Timer(Sender: TObject);
var a, b: integer;
    BreakIt: Boolean;
begin
 // timer interval = 1
 BreakIt := False;
 index := listbox1.ItemIndex;
 IEWndsList.Clear;
 EnumWindows(@EnumIEWndsProc, 0);
 for a := 0 to IEWndsList.Count - 1 do begin
    for b := 0 to ListBox1.Items.Count - 1 do begin
       if IEWndsList[a] <> ListBox1.Items[b] then begin
         ListBox1.Items.Assign(IEWndsList);
         SetHorizontalScroll(ListBox1);
         listbox1.ItemIndex := index;
         BreakIt := True;
         Break;
       end;
    end;
    if BreakIt then Break;
 end;
 // now you wonder why i wrote "if IEWndsList[a]..."? i wrote it
 // because when i select an item in the listbox and it gets
 // updated (by the timer, every 1 ms) and when i right-click
 // on it and want to close the window, it gets unselected.
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
 IEWndsList := TStringList.Create;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
 IEWndsList.Free;
end;

end.