No, incorrect. You obviously don't know your PHP. The slash escapes the quote character so that it can be a string character, in the same way that the "\n"
near the start of that string is an escape sequence that adds a newline. That is why I said that the consideration of the slash character WITHIN the string as a delimiter is arguable. It is not a string character proper, it affects the following character.
The issue is that your code does not interpret the escape slash at all, so it is incorrectly determining the end of the string. It should at the very least understand a \'
combination in a single-quoted string, as well as a \"
combination in a double-quoted string. As Blues would no doubt tell you, an escape slash in strings is prevalent in many languages... probably even Delphi.
I noted in an edit above that the "selected" behaviour was fixed using a combination of 220.127.116.11 HiEditor and 18.104.22.168 HES, it was not working with 22.214.171.124 HiEditor, which I hadn't upgraded to just then.