Detect Code References doesn't work with Regex

Hello,

We're using the Extended Strongly Typed Resource Generator, which generates some extra methods for string formatting in our resources' .Designer.cs files. For example Account.CancelInfo, which got {{0}} in it, will generate Account.CancelInfoFormat(obj arg0) automatically.

We're trying to detect these method references with the following regular expression:
($File.$Key)Format\((\w+,?\W?)+\)


According to multiple expression testers, this pattern matches Account.CancelInfoFormat(xxx). But for some reason we find 0 references:

Do you have an explanation for this, like why doesn't the regular expression match?