fix(ui): keep forced chat scroll above follow lock

vincentkoc · vincentkoc · commit 62be2a28aa14 · 2026-06-13T18:28:35.000+08:00
diff --git a/ui/src/ui/app-scroll.test.ts b/ui/src/ui/app-scroll.test.ts
@@ -232,6 +232,24 @@ describe("scheduleChatScroll", () => {
     expect(container.scrollTop).toBe(container.scrollHeight);
   });
 
+  it("uses force=true on initial load even after a previous follow lock", async () => {
+    const { host, container } = createScrollHost({
+      scrollHeight: 2000,
+      scrollTop: 500,
+      clientHeight: 400,
+    });
+    host.chatUserNearBottom = false;
+    host.chatFollowLocked = true;
+    host.chatHasAutoScrolled = false;
+
+    scheduleChatScroll(host, true);
+    await host.updateComplete;
+
+    expect(container.scrollTop).toBe(container.scrollHeight);
+    expect(host.chatFollowLocked).toBe(false);
+    expect(host.chatNewMessagesBelow).toBe(false);
+  });
+
   it("sets chatNewMessagesBelow when not scrolling due to user position", async () => {
     const { host } = createScrollHost({
       scrollHeight: 2000,
diff --git a/ui/src/ui/app-scroll.ts b/ui/src/ui/app-scroll.ts
@@ -86,10 +86,9 @@ export function scheduleChatScroll(
         manualScroll ||
         autoScrollMode === "always" ||
         (autoScrollMode === "near-bottom" &&
-          !host.chatFollowLocked &&
           (effectiveForce ||
-            host.chatUserNearBottom ||
-            distanceFromBottom < NEAR_BOTTOM_THRESHOLD));
+            (!host.chatFollowLocked &&
+              (host.chatUserNearBottom || distanceFromBottom < NEAR_BOTTOM_THRESHOLD))));
 
       if (!shouldStick) {
         // User is scrolled up — flag that new content arrived below.
@@ -132,10 +131,9 @@ export function scheduleChatScroll(
           manualScroll ||
           autoScrollMode === "always" ||
           (autoScrollMode === "near-bottom" &&
-            !host.chatFollowLocked &&
             (effectiveForce ||
-              host.chatUserNearBottom ||
-              latestDistanceFromBottom < NEAR_BOTTOM_THRESHOLD));
+              (!host.chatFollowLocked &&
+                (host.chatUserNearBottom || latestDistanceFromBottom < NEAR_BOTTOM_THRESHOLD))));
         if (!shouldStickRetry) {
           return;
         }
