Index: trunk/src/layer.c
===================================================================
--- trunk/src/layer.c	(revision 14743)
+++ trunk/src/layer.c	(revision 14744)
@@ -724,20 +724,30 @@
 	return lay;
 }
 
-unsigned int pcb_layer_hash_bound(pcb_layer_t *ly)
+unsigned int pcb_layer_hash_bound(pcb_layer_t *ly, pcb_bool smirror)
 {
 	unsigned int hash;
+	pcb_layer_type_t lyt;
+	int offs;
 
 	assert(ly->is_bound);
 
+	lyt = ly->meta.bound.type;
+	offs = ly->meta.bound.stack_offs;
+
+	if (smirror) {
+		lyt = pcb_layer_mirror_type(lyt);
+		offs = -offs;
+	}
+
 	hash  = (unsigned long)arclist_length(&ly->Arc);
 	hash ^= (unsigned long)linelist_length(&ly->Line);
 	hash ^= (unsigned long)textlist_length(&ly->Text);
 	hash ^= (unsigned long)polylist_length(&ly->Polygon);
-	hash ^= (unsigned long)ly->comb ^ (unsigned long)ly->meta.bound.type;
+	hash ^= (unsigned long)ly->comb ^ (unsigned long)lyt;
 
 	if (ly->meta.bound.type & PCB_LYT_INTERN)
-		hash ^= ly->meta.bound.stack_offs;
+		hash ^= (unsigned int)offs;
 
 	return hash;
 }
Index: trunk/src/layer.h
===================================================================
--- trunk/src/layer.h	(revision 14743)
+++ trunk/src/layer.h	(revision 14744)
@@ -264,7 +264,7 @@
 pcb_layer_t *pcb_layer_new_bound(pcb_data_t *data, pcb_layer_type_t type, const char *name);
 
 /* Calculate a hash of a bound layer (ingoring its name) */
-unsigned int pcb_layer_hash_bound(pcb_layer_t *ly);
+unsigned int pcb_layer_hash_bound(pcb_layer_t *ly, pcb_bool smirror);
 
 /* Calculate mirrored version of some (bound) layer properties */
 pcb_layer_type_t pcb_layer_mirror_type(pcb_layer_type_t lyt);
Index: trunk/src/obj_subc_hash.c
===================================================================
--- trunk/src/obj_subc_hash.c	(revision 14743)
+++ trunk/src/obj_subc_hash.c	(revision 14744)
@@ -59,7 +59,7 @@
 		pcb_text_t *t;
 		pcb_poly_t *p;
 
-		hash ^= pcb_layer_hash_bound(ly);
+		hash ^= pcb_layer_hash_bound(ly, tr.on_bottom);
 
 		linelist_foreach(&ly->Arc, &it, a)
 			hash ^= pcb_arc_hash(&tr, a);