diff --git a/src/eval.c b/src/eval.c
index 4fc9f74..61843bc 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -6640,7 +6640,7 @@
 	    if (HASHITEM_EMPTY(hi))
 		continue;
 	    --todo;
-	    HI2DI(hi)->di_flags = DI_FLAGS_RO | DI_FLAGS_FIX;
+	    HI2DI(hi)->di_flags |= DI_FLAGS_RO | DI_FLAGS_FIX;
 	}
     }
 }