diff --git a/frontend/lib/main.ts b/frontend/lib/main.ts
index f9947ee2..518611cd 100644
--- a/frontend/lib/main.ts
+++ b/frontend/lib/main.ts
@@ -1053,7 +1053,7 @@ const _renderComments = (comments: Comment[]) => {
     commentExpand.addEventListener("click", () => {
       commentExpand.style.display = "none";
       commentFold.style.display = "";
-      commentMain.style.maxHeight = "100%";
+      commentMain.style.maxHeight = commentMain.clientHeight + "px";
       commentMain.style.maxHeight = commentMain.scrollHeight + "px";
     });
     commentFold.addEventListener("click", () => {