data FORMAT forgotten parentheses
diff --git a/src/tree_data.c b/src/tree_data.c
index 72f34d0..d5127d4 100644
--- a/src/tree_data.c
+++ b/src/tree_data.c
@@ -339,7 +339,7 @@
             if (!mod) {
                 break;
             }
-            if (!first || first == *tree) {
+            if (!first || (first == *tree)) {
                 /* make sure first2 changes are carried to tree */
                 first2 = tree;
             } else {