Hopefully advances in coding make the following a possibility now.
When composing a PM, unless you click the "Add" button under recipients, when pressing Submit, the preview screen loads. Unfortunately, many users believe there PM has been submitted.
Replace the "Add" button with what I think is called an onblur event
. (I'm not a coder but I hope that is right.)
This way, the Add button would not be needed at all and the current confusion would not exist.
Thanks to the developers for your continual work,