Not bad. You don't have to jump around your regexp reference and editor. It does not exactly tell you why your exp & string does not match. It just show what typed reg exp will do.
If you don't agree with me, could you perhaps suggest an improvement?
Exp (made it wrong in purpose) ^inout\s+\[[0-9]\: It just display "No Matches".
It would be cool if it kind of guide what exp you want to use to match test string. What you put in Test string is what you want to get.