@Paris Geek: I am not sure why moving to Drafts should be forbidden.
"Drafts" is also a folder. Yes, it has a special functionality, but I am not aware of how being able to move a message to Drafts violates any IMAP specs or spirit of its design.
Why would a user want to do that? I am not "buying" the scenario described by the OP (but again, if someone can use this and it is convenient, - why not?). But I can clearly see an example of the functionality that one may want to have: Thunderbird offers an option of "Edit as new message". This way, you can take a message in Sent, and use it as a template for a new message.
I think moving a message to Drafts should allow to achieve similar functionality. (Actually, in this case "Copy" would be preferred, but as we know, it is, unfortunately, not implemented in Aquamail.)
@dylanme2001:
Messages in [Drafts] in Aquamail should sync with the Drafts folder on the server. This is usually configured by default. And I expect it should happen regardless of how the message ends up in [Drafts].
I suspect that Aquamail doesn't have (or lost) the mapping of the [Drafts] folder to the corresponding folder on Gmail server. (This type of mishaps had been reported by other people, - and it is a glitch on Gmail's side.)
To enable syncing of [Drafts], please follow the instructions described under "How do I access server side folders?" of the Aquamail FAQ:
http://www.aqua-mail.com/?page_id=227