From cfde8f20ee5a42dc31df4991dd4ab17cef5476d6 Mon Sep 17 00:00:00 2001
From: Ajay Bura <32841439+ajbura@users.noreply.github.com>
Date: Mon, 26 Oct 2026 17:02:10 +0530
Subject: [PATCH] prevent scroll from stopping above when decrypting messages
 change view height

---
 src/app/features/room/RoomTimeline.tsx     | 1 +
 src/app/features/room/hooks/useTimeline.ts | 9 +++++----
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/app/features/room/RoomTimeline.tsx b/src/app/features/room/RoomTimeline.tsx
index 399f0f56..b12e9f68 100644
--- a/src/app/features/room/RoomTimeline.tsx
+++ b/src/app/features/room/RoomTimeline.tsx
@@ -201,6 +201,7 @@ export function RoomTimeline({ eventId, roomInputRef, editor, timeline }: RoomTi
   const { markerTs } = useUnreadMarker(atBottomLazy, focused, readReceipt?.ts);
 
   useTimelineContainerResizeStickBottom(
+    timeline,
     getScrollElement,
     useCallback(() => timelineContainerRef.current, []),
     atBottomObservable,
diff --git a/src/app/features/room/hooks/useTimeline.ts b/src/app/features/room/hooks/useTimeline.ts
index 91fea84f..2c52d8e8 100644
--- a/src/app/features/room/hooks/useTimeline.ts
+++ b/src/app/features/room/hooks/useTimeline.ts
@@ -178,6 +178,7 @@ export const useRestoreScrollToBottom = (
 };
 
 export const useTimelineContainerResizeStickBottom = (
+  timeline: TimelineView,
   getScrollElement: () => HTMLElement | null,
   getContainerElement: () => HTMLElement | null,
   atBottomObservable: ObservableValue<boolean>,
@@ -199,12 +200,12 @@ export const useTimelineContainerResizeStickBottom = (
         if (!containerEntry || !scrollElement) return;
 
         if (atBottomObservable.read) {
-          requestAnimationFrame(() => {
-            scrollToBottom(scrollElement, 'smooth');
-          });
+          const batchChange = timeline.batch.read.change;
+          const messageArrived = batchChange.type === 'Grow' && batchChange.dir === 'f';
+          scrollToBottom(scrollElement, messageArrived ? 'smooth' : 'instant');
         }
       };
-    }, [getContainerElement, getScrollElement, atBottomObservable]),
+    }, [timeline, getContainerElement, getScrollElement, atBottomObservable]),
     enable ? getContainerElement : undefined
   );
 };