If the second column does not fit completely in visible area. And user move focus to a file item in that column.
It will only auto scroll that column it if less then 75% is visible.
I had it so it always scrolled if it was not 100% visible. but UI experience was weird, and it would autoscroll in situation where you wonder why it did so, because for the user it was not needed.
However when showing file with the file extension to the right I can see that in this case it might be more of an issue.
So maybe handle it different if that option is on? or maybe always draw the file extension, if column end is out of visible area then move the position where the file extension is drawn so it is always visible? I will do some testing.