Private Const WM_CLOSE As Long = &H10
Private Const WM_QUIT As Long = &H12
 
    Private Sub TextBox_Click()
        Dim H As Long = Me.Handle
        SendMessage(H, WM_CLOSE, vbNull, vbNull)
        SendMessage(H, WM_QUIT, vbNull, vbNull)
    End Sub

An sich gibt es nie Probleme, nur einen Weg, um sie zu l?sen.