Hi,
I'm using Version 4.5.0h (Build 1239) and found a bug that allows users see other users' Sent Mail.
Steps to recreate:

- Login as regular user
- Go to My Account, Edit,
- Remove Email address in Email Options, Save Profile

- Go to emails/Compose email.
--SugarCRM warns, that you are unable to send emails ("Warning: Your email settings are not configured to send email. Edit My Settings"),
- Click on Edit My Settings link
- In My Settings click either Save or Cancel
- SugarCRM displays EMAILS: MY SENT MAIL PAGE but you can see other users' Sent email. You can read others' Sent emails too.

I've checked this conditions on two separate SugarCRM installations

Best regards,
Marek R