avoiding flicker from form child mdi when one child is maximized

frms() is a array of child form mdi

EnumChildWindows frmMdi.hWnd, AddressOf EnumChildProc, 0

Public Function EnumChildProc(ByVal hWnd As Long, ByVal lParam As Long) As Boolean
    Dim strClass As String

    strClass = Space(255)
    ret = GetClassName(hWnd, strClass, 255)
    If Left(strClass, 9) = "MDIClient" Then
        hwndMDI = hWnd ' << hwndMDI is handle of Mdi client
        EnumChildProc = False
    Else
        EnumChildProc = True
    End If
End Function



Private Sub TabStrip_Click()
        .......
    If frms(TabStrip.Tag).WindowState = 2 Then
        ret = ShowWindow(hwndMDI, SW_HIDE)
        frms(TabStrip.SelectedItem.Index).WindowState = 2
        frms(TabStrip.SelectedItem.Index).Hide
        frms(TabStrip.SelectedItem.Index).ZOrder
        frms(TabStrip.SelectedItem.Index).Show
        ret = ShowWindow(hwndMDI, SW_SHOWNA)
    Else
        frms(TabStrip.SelectedItem.Index).ZOrder
    End If
        ........
End Sub