Add new history tab.

        Args:
            filename (str): file to be loaded in a new tab.

def add_history(self, filename, color_scheme, font, wrap):
        """
        Add new history tab.

        Args:
            filename (str): file to be loaded in a new tab.
        """
        filename = encoding.to_unicode_from_fs(filename)
        if filename in self.filenames:
            return
        editor = codeeditor.CodeEditor(self)
        if osp.splitext(filename)[1] == '.py':
            language = 'py'
        else:
            language = 'bat'
        editor.setup_editor(linenumbers=False,
                            language=language,
                            scrollflagarea=False,
                            show_class_func_dropdown=False)
        editor.focus_changed.connect(lambda: self.focus_changed.emit())
        editor.setReadOnly(True)

        editor.set_font(font, color_scheme)
        editor.toggle_wrap_mode(wrap)

        text, _ = encoding.read(filename)
        editor.set_text(text)
        editor.set_cursor_position('eof')

        self.editors.append(editor)
        self.filenames.append(filename)
        index = self.tabwidget.addTab(editor, osp.basename(filename))
        self.find_widget.set_editor(editor)
        self.tabwidget.setTabToolTip(index, filename)
        self.tabwidget.setCurrentIndex(index)