Hope this helps, if my memory serves me right, mail settings is the same in leopard as it was in tiger, so, if you go to preferences -> accounts -> advanced you can check or uncheck "remove copy from server" as in the screenshot i attached. You can also change some stuff around in gmail from your browser...Good luck!
Also, you can change Gmail settings for mail clients to do nothing if the file is deleted from a mail client. I use it that way for the array of mail clients that I use lol
Also, you can change Gmail settings for mail clients to do nothing if the file is deleted from a mail client. I use it that way for the array of mail clients that I use lol