So I'm guessing I'll never know since I deleted it...
But the thing is, I have not used that program in months, then all of a sudden a file from its folder is being flagged as suspicious when I have not touched it...?
There are two possibilities:
1. It was malware all along but the antivirus tool just got improved and now detects it where it did not before.
2. It is a false positive.
Unfortunately, it seems like this particular "Infection: Wind32:Evo-gen [Susp]" is happening all too often (you're not alone), at least some of the time on legitimate files, and it really underscores Avast's inability to deal with false-positives very well.
As it is, by deleting a module from your Fashion Toolbox application, you may well have broken it.
One possibly better approach to dealing with a false positive on that particular file - if you're fairly sure it's legitimate - is to exclude the folder that contains it from Avast scanning. That's a bit extreme, but it will allow you time to both report the false positive and continue working without further interruptions - and without destroying the viability of your program by deleting a portion of it.
I have been through EXACTLY this scenario with this particular "Win32:Evo-gen [Susp]" detection (though not with Fashion Toolbox). A few weeks after having reported it I found it was no longer being falsely detected in the particular files I use and I could remove the folder exclusion.
It's also possible turning down one or some of the sensitivity settings would reduce the chances of this particular false positive, but I don't know which settings that would be.
-Noel