def _justDisplay(self, tool):
        """
        Displays the given tool. Does not register it in the tools list.
        """
        self.header.title.set_text(tool.name)

        body, _options = self.widget.contents["body"]
        overlay = urwid.Overlay(tool.widget, body, *tool.position)
        self._surface = urwid.AttrMap(overlay, "foreground")
        self.widget.contents["body"] = self._surface, None
Displays the given tool. Does not register it in the tools list.