Searching for File name in Open File

Hello All,
Ive been meaning to ask this question for some time. Im using Toad For Oracle 17 and when i go to File the Open File, I try to search for a file name but its not finding the file.
Is this an issue with my OS, my toad settings or something else?
the below example Im searching for my file thats names dba_size. could remember what the exact man was but knew it has size in it but it wouldnt come back. I had to have the start right first

thanks
Dave

You can type in *size*, then hit ENTER, and it will filter the contents above.