GW 8.0.1hp (4400) win xp prof sp3

An attachment opened directly from an email is opened read only and that's not bad.

But what if you answer that email including the attachment and open it now?

Some users start to open attachments via answering / forwarding and change them and after sending the email they wonder why sometimes the changes had no effect.
I might be wrong but I tried to change the attachment a several times and about 1 out of 5 tries the changes had no effect.

Any thoughts about that?