Index: trunk/src/undo_old.c
===================================================================
--- trunk/src/undo_old.c	(revision 17191)
+++ trunk/src/undo_old.c	(revision 17192)
@@ -103,7 +103,7 @@
 	UndoListType *slot = udata;
 #ifndef NDEBUG
 	const char *res = undo_type2str(slot->Type);
-	strcpy(dst, res);
+	pcb_snprintf(dst, dst_len, "%s ser=%d id=%d", res, slot->Serial, slot->ID);
 #else
 	sprintf(dst, "%d", slot->Type);
 #endif