I used latest version of github, just downgrade the raw_controller.rb to version 7.1 cause of the html-raw-view.
Now i see, that the highlightning in codepreview for php files not always show. I found out, if a script-tag is inside the php-file (name.php) the highlighniing is deactivate. If i delete the script-tag highlightning is activate.
Thanks for your help