From 1625b59e43e4a71966cce30d1bdb8ed570db3a2e Mon Sep 17 00:00:00 2001
From: Your Name <your.email@example.com>
Date: Sun, 1 Mar 2026 01:23:04 +0800
Subject: [PATCH] fix(canvas): backfill chat history media into canvas

---
 components/canvas/CanvasChatPanel.tsx | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/components/canvas/CanvasChatPanel.tsx b/components/canvas/CanvasChatPanel.tsx
index b3b264db0..7e0851567 100644
--- a/components/canvas/CanvasChatPanel.tsx
+++ b/components/canvas/CanvasChatPanel.tsx
@@ -2934,11 +2934,7 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
     if (loadedHistorySignatureRef.current === signature) return;
 
     loadedHistorySignatureRef.current = signature;
-    processedMessageIds.current = new Set(
-      historyMessages
-        .filter((message) => message.role === "assistant")
-        .map((message) => message.id)
-    );
+    processedMessageIds.current = new Set();
     hasHydratedHistoryRef.current = true;
     setMessages(historyMessages);
     setMessageViewportKey((prev) => prev + 1);
@@ -3127,6 +3123,17 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
           imageUrlSet.add(rawUrl);
         });
 
+        const legacyContent =
+          typeof (message as any).content === "string"
+            ? (message as any).content
+            : "";
+        if (legacyContent) {
+          extractAssistantImageUrls(legacyContent, nearestUserImageKeys).forEach((url) =>
+            imageUrlSet.add(url)
+          );
+          extractVideoUrls(legacyContent).forEach((url) => videoUrlSet.add(url));
+        }
+
         const imageUrls = Array.from(imageUrlSet);
         const videoUrls = Array.from(videoUrlSet);
         if (imageUrls.length === 0 && videoUrls.length === 0) continue;