Bug in units_dropdown shortcode

Hi.
In coursepress 1.2.4.6 in \includes\classes\class.shortcodes.php line 2599 has to be removed or at least the function sanitize_html_class to be replaced with sanitize_text_field.
Currently the attribute general_title of the shortcode units_dropdown is being stripped from too much characters, including every character in my language and also white space.
Please fix.
Thanks .