Your Visual Regex Explorer link says:
Uses YAPE::Regex::Explain to give detailed explanations of what any valid regex. (As long as it doesn't use any of the extensions added in perl 5.12 or later. That's a limitation of Y::R::E. If it gets updated, then so will VRegExp.)
There is no support for regular expression syntax added after Perl version 5.6, particularly any constructs added in 5.10.