Exclusion of specific file

When developing a demo, OpenFile.exe, avast throws up a suspicious file warning.
Clicking on the “add to exclusions” link on said warning adds “C:\Program Files (x86)\Phix\asm\of\OpenFile.exe”, which does not work.
Adding “C:\Program Files (x86)\Phix\asm\of*” by hand does work.
Attached screenshot deliberately has “oxf” instead of “of”, undoing that makes avast stop giving me false positives.
I also note that the Browse dialog does not allow you to select a specific file, which suggests they ain’t supported and the link/wording should be changed to exclude the entire directory?