The similar tab uses Tinderbox's 'similar to' function to list (up to) 10 items it adjudges most similar to the current note. It replaces the stand-alone minor view in older Tinderbox versions.
Double-clicking any list item sets the clicked note as the focus of the document window's text pane and dismisses the pop-over.
Dragging the pop-over will result in a tear-off window that will persist until the end of the current session (i.e. the document and/or app are closed). A torn-off window may be closed before then if no longer needed.