Index: undo.c
===================================================================
--- undo.c	(revision 9792)
+++ undo.c	(revision 9793)
@@ -168,6 +168,7 @@
 static pcb_bool UndoMoveToLayer(UndoListTypePtr);
 static pcb_bool UndoFlag(UndoListTypePtr);
 static pcb_bool UndoMirror(UndoListTypePtr);
+static pcb_bool UndoOtherSide(UndoListTypePtr);
 static pcb_bool UndoChangeSize(UndoListTypePtr);
 static pcb_bool UndoChange2ndSize(UndoListTypePtr);
 static pcb_bool UndoChangeAngles(UndoListTypePtr);
@@ -574,6 +575,30 @@
 }
 
 /* ---------------------------------------------------------------------------
+ * recovers a subc from an other-side  operation
+ * returns pcb_true if anything has been recovered
+ */
+static pcb_bool UndoOtherSide(UndoListTypePtr Entry)
+{
+	void *ptr1, *ptr2, *ptr3;
+	int type;
+
+	/* lookup entry by ID */
+	type = pcb_search_obj_by_id(PCB->Data, &ptr1, &ptr2, &ptr3, Entry->ID, Entry->Kind);
+	if (type == PCB_TYPE_SUBC) {
+		pcb_subc_t *subc = (pcb_subc_t *)ptr3;
+		if (andDraw)
+			EraseSubc(subc);
+		pcb_subc_change_side(subc, Entry->Data.Move.DY);
+		if (andDraw)
+			DrawSubc(subc);
+		return (pcb_true);
+	}
+	pcb_message(PCB_MSG_ERROR, "hace Internal error: UndoOtherside on object type %x\n", type);
+	return (pcb_false);
+}
+
+/* ---------------------------------------------------------------------------
  * recovers an object from a 'copy' or 'create' operation
  * returns pcb_true if anything has been recovered
  */
@@ -1045,6 +1070,11 @@
 		if (UndoMirror(ptr))
 			return (PCB_UNDO_MIRROR);
 		break;
+
+	case PCB_UNDO_OTHERSIDE:
+		if (UndoOtherSide(ptr))
+			return (PCB_UNDO_OTHERSIDE);
+		break;
 	}
 	return 0;
 }
@@ -1205,6 +1235,19 @@
 }
 
 /* ---------------------------------------------------------------------------
+ * adds an subc to the list of objects tossed to the other side
+ */
+void pcb_undo_add_subc_to_otherside(int Type, void *Ptr1, void *Ptr2, void *Ptr3, pcb_coord_t yoff)
+{
+	UndoListTypePtr undo;
+
+	if (!Locked) {
+		undo = GetUndoSlot(PCB_UNDO_OTHERSIDE, PCB_OBJECT_ID(Ptr3), Type);
+		undo->Data.Move.DY = yoff;
+	}
+}
+
+/* ---------------------------------------------------------------------------
  * adds an object to the list of rotated objects
  */
 void pcb_undo_add_obj_to_rotate(int Type, void *Ptr1, void *Ptr2, void *Ptr3, pcb_coord_t CenterX, pcb_coord_t CenterY, pcb_uint8_t Steps)
@@ -1640,6 +1683,7 @@
 		case PCB_UNDO_CHANGESIZE: return "changesize";
 		case PCB_UNDO_CHANGE2NDSIZE: return "change2ndsize";
 		case PCB_UNDO_MIRROR: return "mirror";
+		case PCB_UNDO_OTHERSIDE: return "otherside";
 		case PCB_UNDO_CHANGECLEARSIZE: return "chngeclearsize";
 		case PCB_UNDO_CHANGEMASKSIZE: return "changemasksize";
 		case PCB_UNDO_CHANGEANGLES: return "changeangles";