(Fset_window_configuration): Be careful when you choose

among several possible points for the new_current_buffer.

1 files changed, 16 insertions, 3 deletions

diff --git a/src/window.c b/src/window.c
index 988b663cbba..1070f8cf37c 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1,7 +1,7 @@
 /* Window creation, deletion and examination for GNU Emacs.
    Does not include redisplay.
-   Copyright (C) 1985,86,87, 1993,94,95,96,97,98, 2000,01,02,03,04
-   Free Software Foundation, Inc.
+   Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1996, 1997, 1998, 2000,
+     2001, 2002, 2003, 2004, 2005  Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -5594,7 +5594,20 @@ the return value is nil.  Otherwise the value is t.  */)
       if (XBUFFER (new_current_buffer) == current_buffer)
         old_point = PT;
       else
-        old_point = BUF_PT (XBUFFER (new_current_buffer));
+        /* BUF_PT (XBUFFER (new_current_buffer)) gives us the position of
+           point in new_current_buffer as of the last time this buffer was
+           used.  This can be non-deterministic since it can be changed by
+           things like jit-lock by mere temporary selection of some random
+           window that happens to show this buffer.
+           So if possible we want this arbitrary choice of "which point" to
+           be the one from the to-be-selected-window so as to prevent this
+           window's cursor from being copied from another window.  */
+        if (EQ (XWINDOW (data->current_window)->buffer, new_current_buffer)
+            /* If current_window = selected_window, its point is in BUF_PT.  */
+            && !EQ (selected_window, data->current_window))
+          old_point = XMARKER (XWINDOW (data->current_window)->pointm)->charpos;
+        else
+          old_point = BUF_PT (XBUFFER (new_current_buffer));
     }
 
   frame = XWINDOW (SAVED_WINDOW_N (saved_windows, 0)->window)->frame;