One pane: With one pane outliners, the content is displayed immediately below the category. A printed legal document is an example of a one-pane document. A web site with a table-of-contents "frame" on the left hand side is similar to a two-pane outline. A Usene t news group is similar to a three pane outline. When writing documents, or organizing ideas for a project (such as a speech, or for software design) I much prefer one pane outlines. I find they are more conducive to collapsing ideas, because you can mix text with categories, rather than radically split ting the organizational technique from the content (as the two and three pane outlines do).