Regex Tester tool window

I am looking for documentation for the Regex Tester tool window, and searching with terms such as 'regex tester' and 'regex tool window' I haven't been able to find anything.

I want to use the tool window to test for matches, but using the Match button, I get nothing, and always end up going online to Rubular (which is great, btw).  The tester doesn't tell me if I should include the delimiters or not, or if it will accept named capture groups, as in the expression below. 

Changing the expression to remove the delimiters and the named matches doesn't change the response of the Match window. 

Thanks - especially if you can point me to the documentation.