Applying mailing template after entering text overwrites the content without saving

Create a mailing with no template. Save it. Go back to edit the mailing and apply a template. The previously-entered text is wiped out even if you have not clicked the "Save Draft" button. I have reproduced this behavior on the demo site, as well.

This would seem to be dangerous and counter-intuitive. If the template cannot be applied to the existing text (and I can think of reasons why that might be the case), still returning to the mailings menu without saving should not destructively replace the text in the mailing.