I've found some strange thing :)
HTML-tags inside of a php-string are highlighted like as HTML tags in HTML-context...and not looks like a part of string at all.
The real pain is:
I'm developing plugin for PhpStorm.
When I'm trying to find HTMLTag-psiElement in php file I get HTMLTag inside of StringLiteralExpression as a result. But it's wrong, html tag must be recognized as a part of string, but not as a part of xml tree.