Re: prefix keymap echoing partly broken

[Richard Stallman]

Those backtraces don't have useful information.

To debug this, I think you need to put breakpoints in the functions in
keyboard.c that do echoing, and see which ones are called and why.

    Maybe this statement isn't
    reached, because there is already `C-x' in the echo area as the
    comment indicates:

I don't understand what you mean by that--have you perhaps misunderstood
the comment?

Anyway, how about putting a breakpoint at this if statement and
examining the data?  That's the way to debug.

    --8<---------------cut here---------------start------------->8---
      if (/* There currently is something in the echo area.  */
          !NILP (echo_area_buffer[0])
          && (/* And it's either not from echoing.  */
              !EQ (echo_area_buffer[0], echo_message_buffer)
              /* Or it's an echo from a different kboard.  */
              || echo_kboard != current_kboard
              /* Or we explicitly allow overwriting whatever there is.  */
              || ok_to_echo_at_next_pause == NULL))
        cancel_echoing ();
      else
        echo_dash ();