Always re-caching email/re-synchronizing w/ server when launching Mail

Question

I had to change my email address on my personal domain I have. for privacy concerns i will just label it 'example.com'.
Iam using IMAP for my domains on a shared hosting account.
My long-term email account is [email protected], however I've had to change it to [email protected] ... so what I did in the cPanel of my websites backend is create a new email account '[email protected]' with the same password as [email protected]
kept [email protected] in the Mail application, added the [email protected] account into Mail and properly copied mail form [email protected] to [email protected] by selecting all inbox messages in [email protected] right-clicking and selecting copy-to -> [email protected]
it reflected this on the server aswell when i check the [email protected] account via webmail (SquirrelMail).
I did the same for Drafts and Sent.
However since I kept both in there to make sure I dont miss a message while I migrate to the new email account [email protected] and [email protected] are always re-caching/re-synchronizing with the server if i ever open Mail after a reboot or closing mail completely.
When it does that I lose all my Rules (and have to re-apply them, which is easy) but it is very frustating as it takes a long while before I can check for new messages and doesnt make sense why it is recaching the mail when it has been fine.
maybe should I have just selected all the mail messages and dragged them to the mailbox instead of doing a copy-to?
Thanks!

Answer 1

I wanted to add more information, hopefully maybe clearing anything issues.
OSX 10.6.6, Mail.app, my own domain using IMAP.
for example my original email address was '[email protected]' and needed to change my email to '[email protected]'
I created the new email account ([email protected]) on my shared hosting account cPanel using the same password as the original email ([email protected]).
Launched mail, the original email ([email protected]) I still kept in Mail, and added the new account ([email protected]) then proceeded to select all the messages from [email protected]'s Inbox to [email protected]'s Inbox...and right-clicked and selected "Copy-To [email protected]'s Inbox" (and the same for the Drafts and Sent folders)... so they were identical and had all my email copied properly over.
Everything looked fine, on the server end using WebMail (SquirrelMail) it showed everything like for like. I can send messages fine, etc.
However whenever I quite Mail and reopened it (didnt matter if I shut down the Mac or restarted or just simply relaunched mail) it always recaches the Inboxes for BOTH accounts every single time since I've added the new account as seen below:
Anyway to resolve this?