ExcelVBAでフォームが開いてるか調査

ExcelVBA 
    Dim bOPen_UserForm1 As Boolean: bOPen_UserForm1 = False
    Dim f As UserForm
    For Each f In UserForms
        If TypeOf f Is UserForm1 Then
            bOPen_UserForm1 = True
            'MsgBox "開かれている"
        End If
    Next
    If bOPen_UserForm1 = False Then
        Exit Sub
    End If
    'ダイアログが見えてるか調査
    If UserForm1.Visible = False Then
        Exit Sub
    End If

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