[Non VCL] - Button erscheint nicht...

[Rastaman]

Naja gut ich steh vor dem nächsten Problem mit den Buttons...
Folgendes hab ich bis jetzt:

Code:

program TestProg;

uses
  Windows,
  Messages;

var
  WndMain,
  WndAbout: TWndClassEx;

  hWndMain: HWND;

  //Button Handles

  msg: TMSG;

function WndMainProc(hwnd: HWND; uMsg: UINT; wParam: WPARAM;
                     lParam: LPARAM): LRESULT; stdcall;
var
  hBtnAbout,
  hBtnExit: DWORD;
begin
  case uMsg of
    WM_CREATE: begin
                 hBtnAbout := CreateWindow('BUTTON', 'About',
                            WS_CHILD or WS_VISIBLE,
                            220, 235, 70, 24,
                            hwnd, 0, 0, nil);
                 hBtnExit := CreateWindow('BUTTON', 'Beenden',
                            WS_CHILD or WS_VISIBLE,
                            310, 235, 70, 24,
                            hwnd, 0, 0, nil);
               end;

    WM_DESTROY: PostQuitMessage(0);

[color=red]    WM_COMMAND: if wParam = BN_CLICKED then
                  if lParam = hBtnAbout then
                  begin
                    CreateWindowEx(0,
                                   'wnd_About', 'About',
                                   WS_DLGFRAME  or WS_VISIBLE,
                                   300, 300,
                                   300, 200,
                                   hwnd, 0, 0, nil);
                    EnableWindow(hwnd, False);
                  end else if lParam = hBtnExit then
                    SendMessage(hwnd, WM_DESTROY, 0, 0);

  end;
  Result := DefWindowProc(hwnd, uMsg, wParam, lParam);
end;
[/color]
function WndAboutProc(hwnd: HWND; uMsg: UINT; wParam: WPARAM;
                      lParam: LPARAM): LRESULT; stdcall;
var
  hBtnOk: DWORD;
begin
  case uMsg of
  WM_CREATE: begin
               hBtnOk := CreateWindow('BUTTON', 'OK',
                                      WS_CHILD or WS_VISIBLE,
                                      210, 260,
                                      70, 24,
                                      hwnd, 0, 0, nil);
             end;

  end;
  Result := DefWindowProc(hwnd, uMsg, wParam, lParam);
end;

function RegisterWindowClasses: Boolean;
begin

  WndMain.cbSize := SizeOf(TWndClassEx);
  WndMain.style := CS_OWNDC;
  WndMain.lpfnWndProc := @WndMainProc;
  WndMain.cbClsExtra := 0;
  WndMain.cbWndExtra := 0;
  WndMain.hInstance := hInstance;
  WndMain.hCursor := LoadCursor(0, IDC_ARROW);
  WndMain.hbrBackground := COLOR_BTNSHADOW;
  WndMain.lpszMenuName := nil;
  WndMain.lpszClassName := 'wnd_Root';
  RegisterClassEx(WndMain);

  WndAbout.cbSize := SizeOf(TWndClassEx);
  WndAbout.style := CS_OWNDC;
  WndAbout.lpfnWndProc := @WndAboutProc;
  WndAbout.cbClsExtra := 0;
  WndAbout.cbWndExtra := 0;
  WndAbout.hInstance := hInstance;
  WndAbout.hCursor := LoadCursor(0, IDC_ARROW);
  WndAbout.hbrBackground := COLOR_WINDOW;
  WndAbout.lpszMenuName := nil;
  WndAbout.lpszClassName := 'wnd_About';
  RegisterClassEx(WndAbout);

  Result := True;

end;

begin

  if not RegisterWindowClasses then
    Exit;

  hWndMain := CreateWindowEx(WS_EX_APPWINDOW,
                             'wnd_Root', 'Haupt Fenster',
                             WS_OVERLAPPED or WS_SYSMENU or WS_MINIMIZEBOX or WS_VISIBLE,
                             200, 300,
                             400, 300,
                             0, 0, hInstance, nil);

  while True do
  begin
    if not GetMessage(msg, 0, 0, 0) then
      break;
    TranslateMessage(msg);
    DispatchMessage(msg);
  end;

end.

Das funktioniert nicht.
Wenn ich aber die beiden Buttonvariablen hBtnAbout und hBtnExit als globale Variable deklariere funktioniert es.
Ich habs (wenn die beiden lokal waren) schon mit allem Hi und Lo usw. probiert aber nix klappt...
Woran liegt das