Note that this works whether or not the message was authored with an outliner, even if it was written in a Web browser. Save As HTML To save an outline to disk as HTML, choose Save As HTML from the File menu. If an outline contains rules, it's rendered the same way Manila renders outlines. Save As Plain Text To save an outline as tab-indented text, choose Save As Plain Text from the File menu. Once you have saved an outline as plain text, you can just choose Save next time.
Radio remembers that it's a plain text outline.
Note that when you save as plain text, any node type data is lost. Only the text of the headlines is saved. A use for this feature might be editing Python scripts or Java source code in an outline. Bookmarks and outlines Radio has a Bookmarks menu that works like the Bookmarks or Favorites menu in a Web browser. Look at the menu and see that there's an additional command, Add Boilerplate, that allows you to save often-used bits of outlines and insert them into other outlines.