Somewhat inconvenient feature

[Richard Stallman]

There is a feature that moves window-start to the start of a line
automatically in certain cases.  The purpose of this feature is in
case the start was on a continuation line, and then some change in the
buffer text causes that position not to be the start of a continuation
line any more.

However, the conditions for the feature are too loose, so the
automatic change happens in other circumstances where it is
not desirable.

Can someone please take a look at this code in xdisp.c
and find a better condition for when to call
compute_window_start_on_continuation_line?


  /* When windows_or_buffers_changed is non-zero, we can't rely on
     the window end being valid, so set it to nil there.  */
  if (windows_or_buffers_changed)
    {
      /* If window starts on a continuation line, maybe adjust the
         window start in case the window's width changed.  */
      if (XMARKER (w->start)->buffer == current_buffer)
        compute_window_start_on_continuation_line (w);

      w->window_end_valid = Qnil;
    }