iphone

@pro

This is actually normal behavior when using IMAP protocol to access your email.  This methods allows for a convenient, single, and synchronized view of your email across all devices as how the email remains stored at the server.  If you're simply wanting to remove message from your device but not wanting them deleted entirely you might find it useful to create a folder to hold such messages.  The other alternative is to switch to POP3 protocol to retrieve your email.  This method however deletes the emails from the server which makes the messages only available to the device that downloaded them.