diff --git a/TODO b/TODO
index 10f9013c..66cf7292 100644
--- a/TODO
+++ b/TODO
@@ -1,3 +1,20 @@
+- the change to reduce region churn 
+
+	https://github.com/jcupitt/libvips/commit/6ae1888ab3a078f81fc50a967b38ac2aaefe4187
+
+  has broken sharing, try:
+
+  	vips sharpen k2.jpg x.jpg
+
+  no colour info in x.jpg, we no longer detect and share buffers
+
+  need to clear 'done' on the buffers?
+
+
+
+
+
+
 - some malloc/free cycling in
 
 	vips sharpen in out 
@@ -20,6 +37,8 @@
 
   each image needs a per-thread list of unreffed buffers ready for reuse
 
+  done in branch "reserve", fix master as noted above and merge
+
 
 
 
diff --git a/libvips/iofuncs/buffer.c b/libvips/iofuncs/buffer.c
index 12085865..5f0dc69b 100644
--- a/libvips/iofuncs/buffer.c
+++ b/libvips/iofuncs/buffer.c
@@ -226,6 +226,9 @@ vips_buffer_undone( VipsBuffer *buffer )
 		buffer->done = FALSE;
 		buffer->cache = NULL;
 
+		buffer->area.width = 0;
+		buffer->area.height = 0;
+
 #ifdef DEBUG
 		printf( "vips_buffer_undone: %d buffers left\n",
 			g_slist_length( cache_list->buffers ) );
@@ -318,10 +321,11 @@ buffer_move( VipsBuffer *buffer, VipsRect *area )
 
 	g_assert( buffer->ref_count == 1 );
 
-	buffer->area = *area;
 	vips_buffer_undone( buffer );
 	g_assert( !buffer->done );
 
+	buffer->area = *area;
+
 	new_bsize = (size_t) VIPS_IMAGE_SIZEOF_PEL( im ) * 
 		area->width * area->height;
 	if( buffer->bsize < new_bsize ) {
diff --git a/libvips/iofuncs/region.c b/libvips/iofuncs/region.c
index bbf008e0..f590a6cb 100644
--- a/libvips/iofuncs/region.c
+++ b/libvips/iofuncs/region.c
@@ -41,8 +41,6 @@
  * 	- move invalid stuff to region
  * 3/3/11
  * 	- move on top of VipsObject, rename as VipsRegion
- * 7/12/13
- * 	- delay attached resource unref to reduce malloc/free cycling
  */
 
 /*
@@ -75,8 +73,8 @@
 /*
 #define DEBUG_MOVE 
 #define DEBUG_ENVIRONMENT 1
+#define DEBUG_CREATE
 #define DEBUG
-#define VIPS_DEBUG
  */
 
 #ifdef HAVE_CONFIG_H
@@ -199,7 +197,7 @@ vips_region_finalize( GObject *gobject )
 
 /* Call a start function if no sequence is running on this VipsRegion.
  */
-static int
+int
 vips__region_start( VipsRegion *region )
 {
 	VipsImage *image = region->im;
@@ -229,7 +227,7 @@ vips__region_start( VipsRegion *region )
 
 /* Call a stop function if a sequence is running in this VipsRegion. 
  */
-static void
+void
 vips__region_stop( VipsRegion *region )
 {
 	IMAGE *image = region->im;
@@ -267,7 +265,7 @@ vips_region_dispose( GObject *gobject )
 	VipsImage *image = region->im;
 
 #ifdef VIPS_DEBUG
-	printf( "vips_region_dispose: \n" );
+	VIPS_DEBUG_MSG( "vips_region_dispose: " );
 	vips_object_print_name( VIPS_OBJECT( gobject ) );
 #endif /*VIPS_DEBUG*/
 
@@ -493,10 +491,6 @@ vips_region_new( VipsImage *image )
 {
 	VipsRegion *region;
 
-	/*
-	printf( "vips_region_new: on image %p\n", image ); 
-	 */
-
 	/* Ref quickly, we want to make sure we keep the image around.
 	 * We can't use the property system, we need to be very threaded.
 	 */
@@ -570,17 +564,18 @@ vips_region_buffer( VipsRegion *reg, VipsRect *r )
 	 * If not, try to reuse the current buffer.
 	 */
 	if( reg->invalid ) {
+		if( reg->buffer ) 
+			vips_buffer_undone( reg->buffer );
 		reg->invalid = FALSE;
-		VIPS_FREEF( vips_buffer_unref, reg->buffer );
 		if( !(reg->buffer = vips_buffer_new( im, &clipped )) ) 
 			return( -1 );
 	}
 	else {
-		/* Don't unref the old buffer ... we combine buffer unref 
+		/* Don't call vips_region_reset() ... we combine buffer unref 
 		 * and new buffer ref in one call to reduce malloc/free 
 		 * cycling.
 		 */
-		reg->invalid = FALSE;
+		VIPS_FREEF( vips_window_unref, reg->window );
 		if( !(reg->buffer = 
 			vips_buffer_unref_ref( reg->buffer, im, &clipped )) ) 
 			return( -1 );
@@ -637,11 +632,14 @@ vips_region_image( VipsRegion *reg, VipsRect *r )
 
 	if( image->data ) {
 		/* We have the whole image available ... easy!
-		 *
-		 * We can't just set valid = clipped, since this may be an
+		 */
+		if( reg->buffer ) 
+			vips_buffer_undone( reg->buffer );
+		reg->invalid = FALSE;
+
+		/* We can't just set valid = clipped, since this may be an
 		 * incompletely calculated memory buffer. Just set valid to r.
 		 */
-		reg->invalid = FALSE;
 		reg->valid = clipped;
 		reg->bpl = VIPS_IMAGE_SIZEOF_LINE( image );
 		reg->data = VIPS_IMAGE_ADDR( image, clipped.left, clipped.top );
@@ -656,6 +654,7 @@ vips_region_image( VipsRegion *reg, VipsRect *r )
 			reg->window->top + reg->window->height < 
 				clipped.top + clipped.height ) {
 			reg->invalid = FALSE;
+
 			VIPS_FREEF( vips_window_unref, reg->window );
 			if( !(reg->window = vips_window_ref( image, 
 				clipped.top, clipped.height )) )
@@ -783,6 +782,11 @@ vips_region_region( VipsRegion *reg,
 
 	/* Init new stuff.
 	 */
+	if( reg->buffer ) {
+		vips_buffer_undone( reg->buffer );
+		reg->buffer->area.width = 0;
+		reg->buffer->area.height = 0;
+	}
 	reg->invalid = FALSE;
 	reg->valid = final;
 	reg->bpl = dest->bpl;