diff --git a/mode-tree.c b/mode-tree.c
index 5a213df4..fa251c8d 100644
--- a/mode-tree.c
+++ b/mode-tree.c
@@ -497,7 +497,7 @@ mode_tree_build(struct mode_tree_data *mtd)
 	mode_tree_clear_lines(mtd);
 	mode_tree_build_lines(mtd, &mtd->children, 0);
 
-	if (tag == UINT64_MAX)
+	if (mtd->line_list != NULL && tag == UINT64_MAX)
 		tag = mtd->line_list[mtd->current].item->tag;
 	mode_tree_set_current(mtd, tag);