A little tricky, but can't think of why it wouldn't work. There is one case you missed - if I select the entire result line including the newline afterwards, the result of worksheet.get_text() is "" not "\n" - I just changed the code to:

        # Coming up with nothing means either the user selected nothing, or the
        # selection was entirely within one result; in the second case, the user
        # wanted the result text.
        if text == "" or text == "\n":
            text = self.get_text(start, end)

(Adding the comment as well)