User blog comment:Ducksoup/Visual Editor Gets an Update/@comment-13918697-20150329000235/@comment-24036697-20150330205950

Whoa, dude, calm down. This was announced on March 9th, and was rolled out in the past week I believe.

Check out this blog for more info: Syntax highlighting - helping you read and write code

You can always turn the highlighting off in your preferences if you don't like it. :)