How do emails get into the ‘deleted items’ subfolder of the ‘storage folders’ folder of WLM?

Hi,

I've just looked in the 'deleted items' subfolder of the 'storage folders' of WLM and found  - much to my surprise - that 1). there were many sub-sub-folders in the 'deleted items' sub-folder that I was not aware I'd ever created, most of them empty but some not and 2). there were many emails directly in the 'deleted items' folder, some of them not yet read.

My question - how did those folders - and emails - get there?

My normal practise when receiving emails is to read them and then either 1. file them in a folder I've created within the 'storage folders' directory (and never delete them) or 2. delete them, in which case they go into the 'deleted items' folder of my main account (Inbox /  Drafts /  Sent Items / Junk /  Deleted items).

At no time do I ever (consciously at any rate) put anything into the 'deleted items' sub-folder of the 'storage folders' folder.