A short while ago, something was changed with PHP syntax highlighting. Now it appears to be required to always write
```php <?php // … ```
i.e. including the PHP open tag - otherwise the following PHP code will not actually be syntax highlighted.
Why was this changed? It’s an unnecessary nuissance and semantically wrong in my opinion. Most of the time you are posting snippets and examples of PHP code, not fully fledged classes from beginning to end. Thus it is a bit weird if you simply show parts of your class, without any use statements, but having to include <?php nonetheless. Also it is common (at least in the Symfony documentation for example) to not include the <?php open tag in code examples.