The HTML syntax actually opens certain types of what are generally considered to be php files e.g. phtml, inc, tmpl, tpl. The PHP syntax i.e. source.php is a subset of the HTML syntax.
The syntaxes are based on a very old version of the Textmate PHP Bundle
. In fact it's based on version from around Feb 2 2012
. It's old.
The newer version of Textmate PHP Bundle makes the above file types like phtml full fledged PHP syntax language types. I've tried to figure out how best to do this with a custom PHP Grammar
(shameless plug). The problem is that the HTML syntax is tied to the PHP syntax it's not just a case of adding the above file types to the syntax definition file types list. Also, it's not neccessarily just a case of converting the existing textmate bundle into a sublime text one because there are dependency issues with other packages.
Make sure you try clearing any sublime text caches and indexes. If you're on Ubuntu check out:
Sublime Text 3: ~/.config/sublime-text-3/Cache and ~/.config/sublime-text-3/Index
I don't know about Sublime Text 2.