Unfortunately, as standard the "Pre" tag inside HTML/CSS is not designed to wrap like other classes. It is possible to make this happen to avoid the long string of text that you may see when the content does not wrap
If you are editing a LiveEditor page, you can go to Page Settings > Other Scripts > Custom CSS and add this:
white-space: pre-wrap; /* css-3 */
white-space: -moz-pre-wrap; /* Mozilla, since 1999 */
white-space: -pre-wrap; /* Opera 4-6 */
white-space: -o-pre-wrap; /* Opera 7 */
This code will make the pre tag content wrap into the box.
If you need to use the pre HTML on another page you will need to add this on the CSS there or add it to your sitewide CSS inside OptimizePress > Dashboard > Global Settings > Custom CSS (Sitewide)