Add current text to combo box history (convenient method).
        If path ends in os separator ("\" windows, "/" unix) remove it.

def add_current_text(self):
        """
        Add current text to combo box history (convenient method).
        If path ends in os separator ("\" windows, "/" unix) remove it.
        """
        text = self.currentText()
        if osp.isdir(text) and text:
            if text[-1] == os.sep:
                text = text[:-1]
        self.add_text(text)