Código para poder agregar un botón de minimizar al userform macro

buenas noches he visto el mismo código en muchas partes pero a mi no me funciona,

'pongo en Modulo

Option Explicit
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function DrawMenuBar Lib "user32" (ByVal hWnd As Long) As Long
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long) As Long
Private Const WS_MINIMIZEBOX As Long = &H20000
Private Const WS_MAXIMIZEBOX As Long = &H10000
Private Const GWL_STYLE As Long = (-16)

'y en Userform

Private Sub UserForm_Initialize()
Dim lngMyHandle As Long, lngCurrentStyle As Long, lngNewStyle As Long
If Application.Version < 9 Then
lngMyHandle = FindWindow("THUNDERXFRAME", Me.Caption)
Else
lngMyHandle = FindWindow("THUNDERDFRAME", Me.Caption)
End If
lngCurrentStyle = GetWindowLong(lngMyHandle, GWL_STYLE)
lngNewStyle = lngCurrentStyle Or WS_MINIMIZEBOX Or WS_MAXIMIZEBOX
SetWindowLong lngMyHandle, GWL_STYLE, lngNewStyle
End Sub

y me da un error por FindWindow error de compilación, no se ha definido sub o función.

Gracias