Currently, SmarterMail is designed to solely save items to the root Drafts folder. If an item is moved to a sub-folder within Drafts, SmarterMail still only recognizes items in the root Drafts folder as having the ability to be edited. So, this isn't a problem per se as SmarterMail is working as designed.

 

Therefore, what I'm going to do is mark this as a Request and change it's status to "Under Consideration" as we would need to modify how the Drafts folder works to enable editable items in Drafts sub-folders.