Meeting reminders disappear when I accept meetings in Outlook Web App [migrated]

I’m using Outlook Web App on Firefox.

• Whenever I get a meeting invitation, it appears in my inbox
• If I accept the invite, the item disappears from my inbox

How do I stop the item from disappearing? I would like to keep it in there since it is easier to track the details of it all in the email, as opposed to the calendar entry that gets created.