Is there a way to edit or delete an existing note made in Note Mode? When I try to click on a note, I can't get access to the note.
OK. If I click on the protein or the base of the note, then the note opens for me to edit or delete (by backspacing over the existing note).
That's one way to work it.
You can use the Lua commands structure.GetNote() and structure.SetNote() to read and set the text in a Note from within a Foldit Recipe. See http://foldit.wikia.com/wiki/Foldit_Lua_Functions for details.