Not a good idea having sub folders of the Inbox
They should be (sub) folders of Local Folders
Re-arrange (drag and drop into Local Folders) and rename them (rightclick and choose rename) so that your list reads
The reason to rename with a number at the front of folders you create is so that they will appear in the order you want as opposed to alphabetical.
These are system folders and should not be tampered with or they will be liable to corrupt and then you will lose all your email that is in them. This is liable to happen when OE6 does it's compacting (tidying up of folders) which it does on every 100 opening of OE.
It is supposed to compact so let it and don't do anything else on pc until it has finished. (it is finicky like that) when it has finished compacting you will find that there are lots of .bak folders in your recycle bin. That is because it does a temporary backup of folders while it is sorting them and then dumps them when it has finished with them. They can safely be 'emptied' from recycle bin without affecting your email in OE.
Now you will find that your folders 'stay put' after OE does it's 'tidying up' (compacting)