How to Turn Off Send in Background
Postbox sends messages in the background instead of keeping the compose window open while the message is sent. Sent status is now displayed in the status bar.
If you prefer to not have messages sent in the background, you can turn this capability off:
- Open the Config Editor
- Type mailnews.sendInBackground into the "Filter:" textbook.
- Double-click on the row for mailnews.sendInBackground to change the value from true to false.