confusion about the bi-direction synchronization

[sssslang <sssslang@xxxxxxxxx>]

Hi there,
I found offlineimap is handy tool which could solve my email synchronization
problem. But I'm confused about the sync mechanism. I use gmail, and have a
remote repository set to "Gmail" and a local repository set to "Maildir".
Then I got local repo perfectly synchronized after I did some change from
web gmail and run offlineimap. But, on the other side, when I change
something in local repo, e.g. write an email and save it as draft, then run
offlineimap, the draft mail is in gmail server while it disappear in local.
I need to run offlineimap again to get the draft back in local.

Did I do something wrong? Or am I missed something?