# File lib/json/editor.rb, line 444
444:       def collapse_expand(item)
445:         if current = selection.selected
446:           if row_expanded?(current.path)
447:             collapse_row(current.path)
448:           else
449:             expand_row(current.path, true)
450:           end
451:         else
452:             toplevel.display_status("Append a node into the root first!")
453:         end
454:       end