diff --git a/src/frame.c b/src/frame.c
index 25c307b3c6a..2b90d9b524c 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -1790,8 +1790,8 @@ do_switch_frame (Lisp_Object frame, int track, int for_deletion, Lisp_Object nor
      with your typing being interpreted in the new frame instead of
      the one you're actually typing in.  */
 
-  /* FIXME/tty: I don't understand this. (The comment aove is from
-     Jim BLandy 1993 BTW.)
+  /* FIXME/tty: I don't understand this. (The comment above is from
+     Jim BLandy 1993 BTW, and the frame_ancestor_p from 2017.)
 
      Setting the last event frame to nil leads to switch-frame events
      being generated even if they normally wouldn't be because the frame