Option Explicit

Const LWA_COLORKEY = &H1
'Const LWA_ALPHA = &H2
Const LWA_ALPHA = &H3
Const GWL_EXSTYLE = (- 20 )
Const WS_EX_LAYERED = &H80000

Private Declare Function GetWindowLong Lib "user32" _
            Alias "GetWindowLongA" _
            (ByVal hWnd As Long, _
            ByVal nIndex 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 SetLayeredWindowAttributes Lib "user32" _
            (ByVal hWnd As Long, _
            ByVal crKey As Long, _
            ByVal bAlpha As Byte, _
            ByVal dwFlags As Long) As Long
            
Private Declare Function GetAncestor Lib "user32" ( _
  ByVal hWnd As Long, ByVal gaFlags As Long) As Long
Private Const GA_PARENT =  1 
Private Const GA_ROOT =  2 
Private Const GA_ROOTOWNER =  3 

'hWnd - манипулятор окна, Layered - степень прозрачности от 0 до 255
Public Sub SetTransparent(hWnd As Long, Layered As Byte)
Dim Ret As Long
'Определяем стиль нужного окна
Ret = GetWindowLong(hWnd, GWL_EXSTYLE)
'Задаём стиль окна как заслоённый
Ret = Ret Or WS_EX_LAYERED
SetWindowLong hWnd, GWL_EXSTYLE, Ret
'Задём степень прозрачности окна
SetLayeredWindowAttributes hWnd,  0 , Layered, LWA_ALPHA
End Sub

Private Sub UserForm_Initialize()
   Dim hWnd As Long
   hWnd = GetAncestor(Frame1.[_GethWnd], GA_ROOT)
   SetTransparent hWnd,  128 
End Sub

   hWnd = GetAncestor(Frame1.[_GethWnd], GA_ROOT)