Merged directory paths are not sorted alphabetically

Previously, I might have a directory structure like this:

somerootdir
    |
    |-aaa
    |-bbb
    |-ccc

if aaa had only one subdirectory foo, then clicking aaa would take me to aaa/foo. That's fine. But, now my directory listing looks like:

somerootdir
    |
    |-bbb
    |-ccc
    |-aaa/foo

Is there an option somewhere I can check to make aaa be alphabetized properly instead of pushed down to where the subdir falls in the alphabet?