Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil)
  redisplay--update-region-highlight(#<window 24 on section-0005-rev-1.5.tex-Region.B->)
  run-hook-with-args(redisplay--update-region-highlight #<window 24 on section-0005-rev-1.5.tex-Region.B->)
  redisplay--pre-redisplay-functions(t)
  apply(redisplay--pre-redisplay-functions t)
  #[128 "\300\301\"\210\300\302\"\207" [apply redisplay--pre-redisplay-functions ignore nil] 4 nil nil](t)
  redisplay_internal\ \(C\ function\)()
  recursive-edit()
  ediff-clone-buffer-for-region-comparison("section-0005-rev-1.5.tex" "-Region.B-")
  ediff-regions-wordwise("section-0005.tex" "section-0005-rev-1.5.tex")
  funcall-interactively(ediff-regions-wordwise "section-0005.tex" "section-0005-rev-1.5.tex")
  call-interactively(ediff-regions-wordwise nil nil)
  command-execute(ediff-regions-wordwise)