[Plugin: WP-Syntax] <?php goes to < ?php

I have the same problem on https://pappmaskin.no/2010/03/how-to-make-the-wordpress-plugin-get_the_image-work-with-timthumb/ but only when its on a new line, the ?php is correct when used inside other html, like the a href in the example on my site.

Why?

Ah, found the solution in another thread: Edit wordpress Settings under Writing and turn off “WordPress should correct invalidly nested XHTML automatically”