Can you provide an option to set the subfolder view as the default?

I used to love fastpictureviewer, but it lacked maintenance for years, So I change to fastrawviewer.
I'm not a shooter, but more a viewer. 
 
Though you are still the fastest pic viewer software I've tried, many functions are too complex for simply a viewer. 
One feature of fastpictureviewer that saved me a lot of time, 
is the subfolder mode. 
I just want to casually walk around folder of pictures, it may hidden in nested folders.
It's really rare to reach depth, folder number, file number limit. 
I don't like the confirm dialog to interrupt my mind flow.
 
Can you provide an option to make "subfolder view" as default, and no annoying confirm dialog box ?
 
Thanks a lot. You did a great job.