* buffer.c (Fset_buffer_multibyte): Do not force redisplay

if changed buffer is not shown in a window.
* insdel.c (prepare_to_modify_buffer): Likewise.
* window.c (replace_buffer_in_windows_safely): Do nothing
if buffer is not shown in a window.
(Fforce_window_update): Likewise if string or buffer argument
is passed.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/buffer.c b/src/buffer.c
index 1194431841a..748422df73a 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2691,10 +2691,11 @@ current buffer is cleared.  */)
 
   UNGCPRO;
 
-  /* Changing the multibyteness of a buffer means that all windows
-     showing that buffer must be updated thoroughly.  */
   current_buffer->prevent_redisplay_optimizations_p = 1;
-  ++windows_or_buffers_changed;
+
+  /* If buffer is shown in a window, let redisplay consider other windows.  */
+  if (buffer_window_count (current_buffer))
+    ++windows_or_buffers_changed;
 
   /* Copy this buffer's new multibyte status
      into all of its indirect buffers.  */