For moving a IMAP folder (or any folder for a matter of fact), there should be a confirmation dialogue to confirm the move. Or at least an option to set for confirmation on folder move or not. As sometimes working on the laptop touchpad, a mistake can happen easily. Moving a folder outside Gmail messes up related filter.
it’s already implemented and will be inculded in version 3.1 which will be released soon.
Really looking forward to 3.1… hope it will have more free account offer or free IM