About set_marker - That's Overdue Color

State sequence of menu choices that lead to the target page where you want your feature. Screenshots would be useful too.

If it is your own page, how can the community help you?

What page in FA are you using as the basis for your page?

Unless we know the context and what includes are available at the point of usage, how can we help you?

set_marker() is a method of class db_pager defined in includes/db_pager.inc. This function marks the rows in a specific way. You may need to extend this class and have one more method say set_marker2() to achieve what you want or modify the functionality of the existing method with an additional argument to flag it differently.

The sample code you are after are in files like:
Line 318 in sales/inquiry/sales_orders_view.php
and
Line 244 in sales/inquiry/customer_inquiry.php

The colors are provided as arguments to the set_marker() function as seen in lines 390-398 of includes/db_pager.inc:

    //    Set check function to mark some rows.
    //    
    function set_marker($func, $notice='', $markercl='overduebg', $msgclass='overduefg' )
    {
        $this->marker = $func;
        $this->marker_txt = $notice;
        $this->marker_class = $markercl;
        $this->notice_class = $msgclass;
    }

The color values of overduebg (background color) and overduefg (text color) for marking purposes are available in the various theme css like in lines 320-326 of themes/default/default.css :

.overduebg {
    background-color: #dd7777;
}

.overduefg {
    color: #dd7777;
}