@[deleted]01: Many thanks for the hint, but changing this line has no effect. This will only disable sanitizing while saving, but if you call the page in the frontend it's sanitized again. The problem is, that osTicket has many places where the code is cleaned, stripped or sanitized.We adjusted redactor, htmlawed and js for this and now we can add classes and attributes in richtext while you are logged in as stuff, clients are not allowed to edit html code. We integrated bootstrap in redactor, so you can see, how the content will look. In the backend everything is fine, we will see content in code tags as not rendered code. But in the frontend html entities < or > are converted again into < > and the code is rendered.At the moment we created a workaround by adding class "displayCode" to a code tag and executing the following javascript $('.displayCode').each(function(i){ $(this).text($(this).html()); });to convert html to plain text in the frontend.We tested the recommended changing in a original version and it has no effects,because the code is sanitized by redactor, too.Any other ideas?