Seems like following is a bug in Gmail system. I was investigating over PHP.Backdrop.Trojan and wanted to show malicious installed.php file to my friend. Here is what I did -
1. Created a reply mail (in Gmail).
2. Attached two files. One of them was malicious ‘installed.php’. The attachment was successful.
3. Saved draft.
4. Clicked ‘Send‘ button, and got confirmation about successful send.
5. Now when I clicked ‘Your message have been sent. View message.‘, voila! nothing happen and it didn’t even showed me my mail.
6. Later after few hour I realized that mail has not been sent and still there as draft!
That’s why they call it beta!
[ Note: Ideally a message with viruses should not circulated. My concern in this post is the invalid message/alert displayed to user! ]