This plugin has been closed as of May 19, 2018 and is not available for download. Reason: Unused.
Nice plugin but one annoying feature. When switching from the text view to visual view, it reverts the pre tags to only have the LANG and removes the line= and file= entries so i have to go back through all posts and re add them. This was resolved by making the changes here in the main.php. Seems the names used in the pre tags cause an issue for html5. https://wordpress.org/support/topic/plugin-wp-codebox-wordpress-editor-just-keep-lang-attribut/