4 files changed, 26 insertions, 9 deletions

diff --git a/src/casefiddle.c b/src/casefiddle.c
index d496ffdf6dd..ca5127d5480 100644
--- a/src/casefiddle.c
+++ b/src/casefiddle.c
@@ -117,8 +117,8 @@ casify_region (flag, b, e)
     return;
 
   validate_region (&b, &e);
-  modify_region (XFASTINT (b), XFASTINT (e));
-  record_change (XFASTINT (b), XFASTINT (e) - XFASTINT (b));
+  modify_region (current_buffer, XFASTINT (b), XFASTINT (e));
+  record_change (current_buffer, XFASTINT (b), XFASTINT (e) - XFASTINT (b));
 
   for (i = XFASTINT (b); i < XFASTINT (e); i++)
     {
diff --git a/src/editfns.c b/src/editfns.c
index 7b3db6203d3..86d292f2976 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -1001,7 +1001,7 @@ and don't mark the buffer as really changed.")
   stop = XINT (end);
   look = XINT (fromchar);
 
-  modify_region (pos, stop);
+  modify_region (current_buffer, pos, stop);
   if (! NILP (noundo))
     {
       if (MODIFF - 1 == current_buffer->save_modified)
@@ -1051,7 +1051,7 @@ for the character with code N.  Returns the number of characters changed.")
 
   pos = XINT (start);
   stop = XINT (end);
-  modify_region (pos, stop);
+  modify_region (current_buffer, pos, stop);
 
   cnt = 0;
   for (; pos < stop; ++pos)
diff --git a/src/insdel.c b/src/insdel.c
index a1b3b1ff113..9d2572bfe62 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -473,9 +473,19 @@ del_range (from, to)
   signal_after_change (from, numdel, 0);
 }
 
-modify_region (start, end)
+/* Call this if you're about to change the region of BUFFER from START
+   to END.  This checks the read-only properties of the region, calls
+   the necessary modification hooks, and warns the next redisplay that
+   it should pay attention to that area.  */
+modify_region (buffer, start, end)
+     struct buffer *buffer;
      int start, end;
 {
+  struct buffer *old_buffer = current_buffer;
+
+  if (buffer != old_buffer)
+    set_buffer_internal (buffer);
+
   prepare_to_modify_buffer (start, end);
 
   if (start - 1 < beg_unchanged || unchanged_modified == MODIFF)
@@ -484,6 +494,9 @@ modify_region (start, end)
       || unchanged_modified == MODIFF)
     end_unchanged = Z - end;
   MODIFF++;
+
+  if (buffer != old_buffer)
+    set_buffer_internal (old_buffer);
 }
 
 /* Check that it is okay to modify the buffer between START and END.
diff --git a/src/textprop.c b/src/textprop.c
index db618c7e4c7..e651cbf243b 100644
--- a/src/textprop.c
+++ b/src/textprop.c
@@ -312,7 +312,8 @@ add_properties (plist, i, object)
               {
                 record_property_change (i->position, LENGTH (i),
                                         sym1, Fcar (this_cdr), object);
-                modify_region (make_number (i->position),
+                modify_region (XBUFFER (object),
+                               make_number (i->position),
                                make_number (i->position + LENGTH (i)));
               }
 
@@ -329,7 +330,8 @@ add_properties (plist, i, object)
             {
               record_property_change (i->position, LENGTH (i),
                                       sym1, Qnil, object);
-              modify_region (make_number (i->position),
+              modify_region (XBUFFER (object),
+                             make_number (i->position),
                              make_number (i->position + LENGTH (i)));
             }
           i->plist = Fcons (sym1, Fcons (val1, i->plist));
@@ -367,7 +369,8 @@ remove_properties (plist, i, object)
               record_property_change (i->position, LENGTH (i),
                                       sym, Fcar (Fcdr (current_plist)),
                                       object);
-              modify_region (make_number (i->position),
+              modify_region (XBUFFER (object),
+                             make_number (i->position),
                              make_number (i->position + LENGTH (i)));
             }
 
@@ -386,7 +389,8 @@ remove_properties (plist, i, object)
                 {
                   record_property_change (i->position, LENGTH (i),
                                           sym, Fcar (Fcdr (this)), object);
-                  modify_region (make_number (i->position),
+                  modify_region (XBUFFER (object),
+                                 make_number (i->position),
                                  make_number (i->position + LENGTH (i)));
                 }