I am able to achieve by
Private Sub Form_Load()
Dim lR As Long
lR = SetTopMostWindow(Form2.hwnd, True)
End Sub
and added a module
Option Explicit
Public Const SWP_NOMOVE = 2
Public Const SWP_NOSIZE = 1
Public Const FLAGS = SWP_NOMOVE Or SWP_NOSIZE
Public Const HWND_TOPMOST = -1
Public Const HWND_NOTOPMOST = -2
Declare Function SetWindowPos Lib "user32" _
(ByVal hwnd As Long, _
ByVal hWndInsertAfter As Long, _
ByVal x As Long, _
ByVal y As Long, _
ByVal cx As Long, _
ByVal cy As Long, _
ByVal wFlags As Long) As Long
Public Function SetTopMostWindow(hwnd As Long, Topmost As Boolean) _
As Long
If Topmost = True Then
SetTopMostWindow = SetWindowPos(hwnd, HWND_TOPMOST, 0, 0, 0, _
0, FLAGS)
Else
SetTopMostWindow = SetWindowPos(hwnd, HWND_NOTOPMOST, 0, 0, _
0, 0, FLAGS)
SetTopMostWindow = False
End If
End Function
One can refer to https://support.microsoft.com/en-us/kb/184297
Thanks