diff --git a/frontend/src/hooks/useBotsSync.ts b/frontend/src/hooks/useBotsSync.ts
index 685157c..e79d64a 100644
--- a/frontend/src/hooks/useBotsSync.ts
+++ b/frontend/src/hooks/useBotsSync.ts
@@ -88,6 +88,48 @@ function normalizeMessageId(raw: unknown): number | undefined {
   return i > 0 ? i : undefined;
 }
 
+function mergeLatestMessages(existing: ChatMessage[], latestPage: ChatMessage[]): ChatMessage[] {
+  if (latestPage.length <= 0) {
+    return existing.slice(-300);
+  }
+
+  const latestIds = latestPage
+    .map((msg) => normalizeMessageId(msg.id))
+    .filter((id): id is number => typeof id === 'number');
+  const oldestLatestId = latestIds.length > 0 ? Math.min(...latestIds) : null;
+  const latestIdSet = new Set(latestIds);
+  const latestFallbackKeys = new Set(
+    latestPage
+      .filter((msg) => !normalizeMessageId(msg.id))
+      .map((msg) => `k:${msg.role}:${msg.ts}:${msg.text}`),
+  );
+
+  const keptExisting = existing.filter((msg) => {
+    const id = normalizeMessageId(msg.id);
+    if (id && oldestLatestId !== null && id >= oldestLatestId) {
+      return latestIdSet.has(id);
+    }
+    if (!id && latestFallbackKeys.has(`k:${msg.role}:${msg.ts}:${msg.text}`)) {
+      return false;
+    }
+    return true;
+  });
+
+  const mergedMap = new Map<string, ChatMessage>();
+  [...keptExisting, ...latestPage].forEach((msg) => {
+    const id = normalizeMessageId(msg.id);
+    const key = id ? `id:${id}` : `k:${msg.role}:${msg.ts}:${msg.text}`;
+    mergedMap.set(key, msg);
+  });
+
+  return Array.from(mergedMap.values())
+    .sort((a, b) => {
+      if (a.ts !== b.ts) return a.ts - b.ts;
+      return Number(a.id || 0) - Number(b.id || 0);
+    })
+    .slice(-300);
+}
+
 function normalizeChannelName(raw: unknown): string {
   const channel = String(raw || '').trim().toLowerCase();
   if (channel === 'dashboard_channel' || channel === 'dashboard-channel') return 'dashboard';
@@ -195,19 +237,8 @@ export function useBotsSync(forcedBotId?: string, enableMonitorSockets: boolean
           .filter((msg) => msg.text.trim().length > 0 || (msg.attachments || []).length > 0)
           .slice(-300);
 
-        // Keep already lazy-loaded history; only merge/refresh the latest page.
         const existing = (activeBotsRef.current[target]?.messages || []).filter((m) => (m.kind || 'final') !== 'progress');
-        const mergedMap = new Map<string, ChatMessage>();
-        [...existing, ...latestPage].forEach((msg) => {
-          const key = msg.id ? `id:${msg.id}` : `k:${msg.role}:${msg.ts}:${msg.text}`;
-          if (!mergedMap.has(key)) mergedMap.set(key, msg);
-        });
-        const messages = Array.from(mergedMap.values())
-          .sort((a, b) => {
-            if (a.ts !== b.ts) return a.ts - b.ts;
-            return Number(a.id || 0) - Number(b.id || 0);
-          })
-          .slice(-300);
+        const messages = mergeLatestMessages(existing, latestPage);
         setBotMessages(target, messages);
 
         const lastUser = [...messages].reverse().find((m) => m.role === 'user');
diff --git a/frontend/src/modules/dashboard/hooks/useDashboardChatMessageActions.ts b/frontend/src/modules/dashboard/hooks/useDashboardChatMessageActions.ts
index 3892785..c815858 100644
--- a/frontend/src/modules/dashboard/hooks/useDashboardChatMessageActions.ts
+++ b/frontend/src/modules/dashboard/hooks/useDashboardChatMessageActions.ts
@@ -112,42 +112,7 @@ export function useDashboardChatMessageActions({
     return matched?.id || null;
   }, [hydrateLatestMessages, selectedBotId]);
 
-  const removeConversationMessageLocally = useCallback((message: ChatMessage, deletedMessageId: number) => {
-    if (!selectedBotId) return;
-    const originalMessageId = Number(message.id);
-    const hasOriginalId = Number.isFinite(originalMessageId) && originalMessageId > 0;
-    const idsToRemove = new Set<number>([deletedMessageId]);
-    if (hasOriginalId) {
-      idsToRemove.add(originalMessageId);
-    }
-
-    const scrollBox = chatScrollRef.current;
-    const prevTop = scrollBox?.scrollTop ?? null;
-    const normalizedTargetText = message.role === 'user'
-      ? normalizeUserMessageText(message.text)
-      : normalizeAssistantMessageText(message.text);
-    const targetAttachments = JSON.stringify(message.attachments || []);
-
-    const nextMessages = messages.filter((row) => {
-      const rowId = Number(row.id);
-      if (Number.isFinite(rowId) && rowId > 0) {
-        return !idsToRemove.has(rowId);
-      }
-      if (hasOriginalId || row.role !== message.role) {
-        return true;
-      }
-      const normalizedRowText = row.role === 'user'
-        ? normalizeUserMessageText(row.text)
-        : normalizeAssistantMessageText(row.text);
-      return !(
-        normalizedRowText === normalizedTargetText
-        && JSON.stringify(row.attachments || []) === targetAttachments
-        && Math.abs((row.ts || 0) - (message.ts || 0)) <= 1000
-      );
-    });
-
-    setBotMessages(selectedBotId, nextMessages);
-
+  const preserveChatScrollAfterMessagesChange = useCallback((prevTop: number | null) => {
     if (prevTop === null || chatAutoFollowRef.current) return;
     requestAnimationFrame(() => {
       const box = chatScrollRef.current;
@@ -155,7 +120,33 @@ export function useDashboardChatMessageActions({
       const maxTop = Math.max(0, box.scrollHeight - box.clientHeight);
       box.scrollTop = Math.min(prevTop, maxTop);
     });
-  }, [chatAutoFollowRef, chatScrollRef, messages, selectedBotId, setBotMessages]);
+  }, [chatAutoFollowRef, chatScrollRef]);
+
+  const removeConversationMessageLocally = useCallback((deletedMessageId: number, originalMessageId?: number) => {
+    if (!selectedBotId) return;
+    const originalId = Number(originalMessageId);
+    const idsToRemove = new Set<number>([deletedMessageId]);
+    if (Number.isFinite(originalId) && originalId > 0) {
+      idsToRemove.add(originalId);
+    }
+
+    const scrollBox = chatScrollRef.current;
+    const prevTop = scrollBox?.scrollTop ?? null;
+    const nextMessages = messages.filter((row) => {
+      const rowId = Number(row.id);
+      return !(Number.isFinite(rowId) && rowId > 0 && idsToRemove.has(rowId));
+    });
+    setBotMessages(selectedBotId, nextMessages);
+    preserveChatScrollAfterMessagesChange(prevTop);
+  }, [chatScrollRef, messages, preserveChatScrollAfterMessagesChange, selectedBotId, setBotMessages]);
+
+  const refreshConversationMessages = useCallback(async () => {
+    if (!selectedBotId) return;
+    const scrollBox = chatScrollRef.current;
+    const prevTop = scrollBox?.scrollTop ?? null;
+    await hydrateLatestMessages(selectedBotId);
+    preserveChatScrollAfterMessagesChange(prevTop);
+  }, [chatScrollRef, hydrateLatestMessages, preserveChatScrollAfterMessagesChange, selectedBotId]);
 
   const deleteConversationMessageOnServer = useCallback(async (messageId: number) => {
     await axios.delete(`${APP_ENDPOINTS.apiBase}/bots/${selectedBotId}/messages/${messageId}`);
@@ -166,7 +157,9 @@ export function useDashboardChatMessageActions({
       notify(t.deleteMessagePending, { tone: 'warning' });
       return;
     }
-    let targetMessageId = Number(message.id);
+    const originalMessageId = Number(message.id);
+    const hasOriginalMessageId = Number.isFinite(originalMessageId) && originalMessageId > 0;
+    let targetMessageId = originalMessageId;
     if (!Number.isFinite(targetMessageId) || targetMessageId <= 0) {
       targetMessageId = Number(await resolveMessageIdFromLatest(message));
     }
@@ -189,7 +182,11 @@ export function useDashboardChatMessageActions({
     setDeletingMessageIdMap((prev) => ({ ...prev, [targetMessageId]: true }));
     try {
       await deleteConversationMessageOnServer(targetMessageId);
-      removeConversationMessageLocally(message, targetMessageId);
+      if (hasOriginalMessageId) {
+        removeConversationMessageLocally(targetMessageId, originalMessageId);
+      } else {
+        await refreshConversationMessages();
+      }
       notify(t.deleteMessageDone, { tone: 'success' });
     } catch (error: unknown) {
       notify(resolveApiErrorMessage(error, t.deleteMessageFail), { tone: 'error' });
@@ -200,7 +197,7 @@ export function useDashboardChatMessageActions({
         return next;
       });
     }
-  }, [confirm, deleteConversationMessageOnServer, deletingMessageIdMap, notify, removeConversationMessageLocally, resolveMessageIdFromLatest, selectedBotId, t]);
+  }, [confirm, deleteConversationMessageOnServer, deletingMessageIdMap, notify, refreshConversationMessages, removeConversationMessageLocally, resolveMessageIdFromLatest, selectedBotId, t]);
 
   return {
     deleteConversationMessage,