widget: CalculatorPopup
GtkWindow(): title=None, hidden
  GtkFrame():
    GtkAlignment():
      GtkVBox(main_box): hidden
        GtkVBox(main_widget, expand=True, fill=True):
          GtkLabel(_main_label, expand=True, fill=True):
          ProxyEntry(_entry, expand=True, fill=True): ''
          GtkHBox(expand=True, fill=True):
            GtkLabel(_label, expand=True, fill=True):
            GtkImage(_warning): hidden
