Visual Studio PHP Tools not formatting code

Question

I'm writing php in Visual Studio using the PHP Tools extension. The code formatting of the PHP Tools doesn't seem to be working.

The formatting option is available in the options menu:

And I have tried linking the php-extension to the PHP Editor:

But nothing seems to work. When I try right-clicking a php document and choose Formatting and Validation it goes straight to HTML (Web Forms).

The problem seems to lie with Visual Studio not recognizing php as a language. Anybody an idea? Thanks in advance.