Searching for PID in Activity Monitor non-functional

I am trying to filter activity by PID in Activity Monitor. I see the PID in the list of All Processes, but when I enter its number in the search filter it's not listed. There used to be an option in the search field to choose what to search for - that is not showing up when entering a search.

Any ideas how to Reset this app?

Is there a cache or prefs file?

Thanks.