Fix unread divider: update sessionUnreadRef when messages are marked as read

client-web/src/modules/chats/presentation/components/ChatView.tsx

@@ -187,12 +187,31 @@ export default function ChatView({ onStartCall, onStartGroupCall }: { onStartCal
   // Refs and logic for tracking session's first unread message to show the divider exactly once per load
   const sessionUnreadRef = useRef<{ chatId: string, msgId: string | null }>({ chatId: '', msgId: null });
 
-  if (activeChat && activeChat !== sessionUnreadRef.current.chatId && !isLoadingMessages) {
+  // Update sessionUnreadRef when chat changes OR when messages are marked as read
+  useEffect(() => {
+    if (!activeChat || isLoadingMessages) return;
+
+    // Reset on chat change
+    if (activeChat !== sessionUnreadRef.current.chatId) {
       const firstUnreadMsg = chatMessages.find(
         (m) => m.senderId !== user?.id && !m.readBy?.some((r) => r.userId === user?.id)
       );
       sessionUnreadRef.current = { chatId: activeChat, msgId: firstUnreadMsg ? firstUnreadMsg.id : null };
+    } else {
+      // Update if the first unread message was read (msgId no longer exists in unread list)
+      const firstUnreadMsg = chatMessages.find(
+        (m) => m.senderId !== user?.id && !m.readBy?.some((r) => r.userId === user?.id)
+      );
+      if (sessionUnreadRef.current.msgId && !firstUnreadMsg) {
+        // All messages are now read
+        sessionUnreadRef.current.msgId = null;
+      } else if (firstUnreadMsg && sessionUnreadRef.current.msgId !== firstUnreadMsg.id) {
+        // First unread changed (some messages were read)
+        sessionUnreadRef.current.msgId = firstUnreadMsg.id;
       }
+    }
+  }, [activeChat, chatMessages, user?.id, isLoadingMessages]);
+
   const firstUnreadId = activeChat === sessionUnreadRef.current.chatId ? sessionUnreadRef.current.msgId : null;
   const initialScrollChatId = useRef<string | null>(null);