Do any regular expression fiddlers fully support lookbehind?

Question

I'm looking to test a regular expression that includes lookbehind with possibly infinite repetition. E.g:

(?<!this can't appear anywhere before.*)text to match

This is just an example - the actual regex is nothing like this so please don't answer with alternative ways of doing this!

According to http://www.regular-expressions.info/lookaround.html, this would be supported by .NET but I couldn't get it to work in any of the regex fiddlers I've tried. Just wondering if anyone has seen this problem or knows of a regex fiddler (ideally online) that uses the .NET framework as its engine?

EDIT: At the time of writing this has 3 close votes and some comments below about being off topic. But the FAQ includes "Software development tools" in its tick list of acceptable questions. As the question relates to a fairly advanced regular expression feature I thought it would be best targeted towards the programmer community. Also think it could be of interest to others here so would be worth being recorded as a question rather than a fragment of chatroom conversation. This is just my 2p-worth, am sure there will be those who disagree - but at least please brush up on the rules (e.g. see here and here) before close-voting.

Answer 1

Please note that this question is off-topic for SO. It might be better suited for superuser.com, a sister site of SO.

Otherwise, one site you can use is regexhero.net. Not as userfriendly as some other online regex testers as you cannot quickly copy from there and it frequently bugs you for buying it, but the primary purpose is available.