great except columns not aligned in IE8

I’m pretty sure wp_autop inserts an unneeded paragraph closing tag, that results in invalid html & IE8 display problems. To work around this issue, I created a column container shortcode like this:

function column_container_shortcode($atts, $content) {
        return do_shortcode($content);
    }
add_shortcode('column_container', 'column_container_shortcode')

Then, I enclose the columns inside [column_container][/column_container], which applies the shortcode_unautop filter to the combined columns. I don’t have the luxury of ignoring IE8 problems.