Regex Exclude Paths in 404 Monitor does not seem to work properly

Hello,
I’m trying to exclude static files from recorded in 404 Monitor.

I have used this is Regex: \.[a-zA-Z0-9]+$ in the exclude path.

So, If foo.css or foo.js does not found then 404 Monitor won’t keep a record.

I have also tested the Regex in regex101.com and the result are fine, you can check the regex here.

Screenshot – https://s.put.re/y9jpNcUP.png

But unfortunately 404 Monitor not excluding them.
What is wrong?