Index: trunk/src/buffer.c
===================================================================
--- trunk/src/buffer.c	(revision 28728)
+++ trunk/src/buffer.c	(revision 28729)
@@ -663,7 +663,7 @@
 				pcb_line_t *nline = pcb_lineop_copy(&ctx, destlayer, line);
 				if (nline != NULL) {
 					if (keep_id)
-						nline->ID = line->ID;
+						pcb_obj_change_id((pcb_any_obj_t *)nline, line->ID);
 					changed = 1;
 				}
 			}
@@ -673,7 +673,7 @@
 				pcb_arc_t *narc = pcb_arcop_copy(&ctx, destlayer, arc);
 				if (narc != NULL) {
 					if (keep_id)
-						narc->ID = arc->ID;
+						pcb_obj_change_id((pcb_any_obj_t *)narc, arc->ID);
 					changed = 1;
 				}
 			}
@@ -683,7 +683,7 @@
 				pcb_text_t *ntext = pcb_textop_copy(&ctx, destlayer, text);
 				if (ntext != NULL) {
 					if (keep_id)
-						ntext->ID = text->ID;
+						pcb_obj_change_id((pcb_any_obj_t *)ntext, text->ID);
 					changed = 1;
 				}
 			}
@@ -693,7 +693,7 @@
 				pcb_poly_t *npoly = pcb_polyop_copy(&ctx, destlayer, polygon);
 				if (npoly != NULL) {
 					if (keep_id)
-						npoly->ID = polygon->ID;
+						pcb_obj_change_id((pcb_any_obj_t *)npoly, polygon->ID);
 					changed = 1;
 				}
 			}
@@ -712,7 +712,7 @@
 		nsubc = pcb_subcop_copy(&ctx, subc);
 		if (nsubc != NULL) {
 			if (keep_id)
-				nsubc->ID = subc->ID;
+				pcb_obj_change_id((pcb_any_obj_t *)nsubc, subc->ID);
 			changed = 1;
 		}
 	}
@@ -741,7 +741,7 @@
 			nps = pcb_pstkop_copy(&ctx, padstack);
 			if (nps != NULL) {
 				if (keep_id)
-					nps->ID = padstack->ID;
+					pcb_obj_change_id((pcb_any_obj_t *)nps, padstack->ID);
 				changed = 1;
 			}
 		}
Index: trunk/src/obj_arc.c
===================================================================
--- trunk/src/obj_arc.c	(revision 28728)
+++ trunk/src/obj_arc.c	(revision 28729)
@@ -394,7 +394,7 @@
 		Arc->Thickness, Arc->Clearance, pcb_flag_mask(Arc->Flags, PCB_FLAG_FOUND | ctx->buffer.extraflg), pcb_false);
 
 	pcb_arc_copy_meta(a, Arc);
-	if (ctx->buffer.keep_id) a->ID = Arc->ID;
+	if (ctx->buffer.keep_id) pcb_obj_change_id((pcb_any_obj_t *)a, Arc->ID);
 	return a;
 }
 
Index: trunk/src/obj_common.c
===================================================================
--- trunk/src/obj_common.c	(revision 28728)
+++ trunk/src/obj_common.c	(revision 28729)
@@ -385,3 +385,20 @@
 		default: break;
 	}
 }
+
+void pcb_obj_change_id(pcb_any_obj_t *obj, long int new_id)
+{
+	pcb_data_t *data;
+
+	if (obj->parent_type == PCB_PARENT_DATA)
+		data = obj->parent.data;
+	else if (obj->parent_type == PCB_PARENT_LAYER)
+		data = obj->parent.layer->parent.data;
+	else
+		return;
+
+	pcb_obj_id_del(data, obj);
+	obj->ID = new_id;
+	pcb_obj_id_reg(data, obj);
+}
+
Index: trunk/src/obj_common.h
===================================================================
--- trunk/src/obj_common.h	(revision 28728)
+++ trunk/src/obj_common.h	(revision 28729)
@@ -235,6 +235,8 @@
 void pcb_obj_pre(pcb_any_obj_t *o);
 void pcb_obj_post(pcb_any_obj_t *o);
 
+/* change the ID of an object already registered in the ID hash */
+void pcb_obj_change_id(pcb_any_obj_t *o, long int new_id);
 
 #define pcb_obj_id_reg(data, obj) \
 	do { \
Index: trunk/src/obj_line.c
===================================================================
--- trunk/src/obj_line.c	(revision 28728)
+++ trunk/src/obj_line.c	(revision 28729)
@@ -435,7 +435,7 @@
 															Line->Point2.X, Line->Point2.Y,
 															Line->Thickness, Line->Clearance, pcb_flag_mask(Line->Flags, PCB_FLAG_FOUND | ctx->buffer.extraflg));
 	pcb_line_copy_meta(line, Line);
-	if (ctx->buffer.keep_id) line->ID = Line->ID;
+	if (ctx->buffer.keep_id) pcb_obj_change_id((pcb_any_obj_t *)line, Line->ID);
 	return line;
 }
 
Index: trunk/src/obj_poly.c
===================================================================
--- trunk/src/obj_poly.c	(revision 28728)
+++ trunk/src/obj_poly.c	(revision 28729)
@@ -515,7 +515,7 @@
 	polygon = pcb_poly_new(layer, Polygon->Clearance, Polygon->Flags);
 	pcb_poly_copy(polygon, Polygon, 0, 0);
 	pcb_poly_copy_meta(polygon, Polygon);
-	if (ctx->buffer.keep_id) polygon->ID = Polygon->ID;
+	if (ctx->buffer.keep_id) pcb_obj_change_id((pcb_any_obj_t *)polygon, Polygon->ID);
 
 	/* Update the polygon r-tree. Unlike similarly named functions for
 	 * other objects, CreateNewPolygon does not do this as it creates a
Index: trunk/src/obj_pstk_op.c
===================================================================
--- trunk/src/obj_pstk_op.c	(revision 28728)
+++ trunk/src/obj_pstk_op.c	(revision 28729)
@@ -37,7 +37,7 @@
 
 	npid = pcb_pstk_proto_insert_dup(ctx->buffer.dst, proto, 1);
 	p = pcb_pstk_new_tr(ctx->buffer.dst, -1, npid, ps->x, ps->y, ps->Clearance, pcb_flag_mask(ps->Flags, PCB_FLAG_FOUND | ctx->buffer.extraflg), ps->rot, ps->xmirror, ps->smirror);
-	if (ctx->buffer.keep_id) p->ID = ps->ID;
+	if (ctx->buffer.keep_id) pcb_obj_change_id((pcb_any_obj_t *)p, ps->ID);
 	return pcb_pstk_copy_meta(p, ps);
 }
 
Index: trunk/src/obj_subc.c
===================================================================
--- trunk/src/obj_subc.c	(revision 28728)
+++ trunk/src/obj_subc.c	(revision 28729)
@@ -1407,7 +1407,7 @@
 void *pcb_subcop_add_to_buffer(pcb_opctx_t *ctx, pcb_subc_t *sc)
 {
 	pcb_subc_t *nsc;
-	nsc = pcb_subc_dup_at(NULL, ctx->buffer.dst, sc, 0, 0, pcb_false);
+	nsc = pcb_subc_dup_at(NULL, ctx->buffer.dst, sc, 0, 0, ctx->buffer.keep_id);
 
 	if (ctx->buffer.extraflg & PCB_FLAG_SELECTED) {
 		pcb_undo_freeze_serial();
@@ -1417,8 +1417,6 @@
 		pcb_undo_unfreeze_serial();
 	}
 
-	if (ctx->buffer.keep_id) nsc->ID = sc->ID;
-
 	return nsc;
 }
 
Index: trunk/src/obj_text.c
===================================================================
--- trunk/src/obj_text.c	(revision 28728)
+++ trunk/src/obj_text.c	(revision 28729)
@@ -428,7 +428,7 @@
 	pcb_text_t *t = pcb_text_new(layer, pcb_font(PCB, Text->fid, 1), Text->X, Text->Y, Text->rot, Text->Scale, Text->thickness, Text->TextString, pcb_flag_mask(Text->Flags, ctx->buffer.extraflg));
 
 	pcb_text_copy_meta(t, Text);
-	if (ctx->buffer.keep_id) t->ID = Text->ID;
+	if (ctx->buffer.keep_id) pcb_obj_change_id((pcb_any_obj_t *)t, Text->ID);
 	return t;
 }