Why do SOME folders in the left-side Folders list have dropdown arrows, but others do not, when there are NO sub-folders contained within it?
Just like the title of this post says – Why do SOME folders in the left-side Folders list have dropdown arrows, but others do not, but crucially, when there are NO sub-folders contained within it?
See the attached screengrab.
I have a folder with three other folders contained within it.
Folders 2 and 3 have dropdown arrows, but folder 1 does not.
This would seem to me to indicate that folders 2 and 3 have sub-folders within them, but you'll notice that the dropdown arrow on folder 2 has been clicked on, and is pointing down, but is not showing any folders contained within it.
And believe me, there are no folders within it.
As far as I can tell, each of these three sub-folders is, for all intents and purposes, exactly the same.
They each have a selection of images in them, and that's it. No sub-folders. No hidden files (I have turned on "View > Show Hidden Files" to check).
The images in them are all the same type, just JPGs. They are all named in the same way.
Here's a few steps that confuse things further...
Step 1: If I move a couple of images from folder 2 into folder 1, then I still do not get a dropdown arrow in folder 1.
Step 2: But if I move a couple more images from folder 2 into folder 1, then I DO get a dropdown arrow in folder 1.
Step 3: But it's not those specific images from step 2 that are the problem, because if I keep those there, but move the images from step 1 back into folder 2 from folder 1, then the dropdown arrow disappears again.
Aaaaargh! I just don't get it, and it's driving my OCD to extreme levels!
I'm sick of opening up folders to see the sub-folders, only to find THERE ARE NO SUB-FOLDERS!!!
Can anyone help me out here?
Why is it doing this?
And how can I stop it?
Thanks!

