A "text receiver" is a program that expects to receive text drags, such as a word processor or a Tinderbox text window.
When dragging multiple notes to a text receiver, Tinderbox supplies a list of all the note titles.
When dragging a single note, Tinderbox supplies the styled text of the note if the note's text is not empty. If the note's text is empty, Tinderbox supplies the note title.