diff --git a/domain/adapters/providers/telegram.py b/domain/adapters/providers/telegram.py
index 8f4b445..799bd21 100644
--- a/domain/adapters/providers/telegram.py
+++ b/domain/adapters/providers/telegram.py
@@ -91,6 +91,7 @@ class TelegramAdapter:
         self._client: TelegramClient | None = None
         self._client_lock = asyncio.Lock()
         self._download_lock = asyncio.Lock()
+        self._active_stream_message_id: int | None = None
         self._message_cache: Dict[int, Tuple[float, object]] = {}
 
     @staticmethod
@@ -517,35 +518,7 @@ class TelegramAdapter:
         raise NotImplementedError("Telegram 适配器不支持创建目录。")
 
     async def get_thumbnail(self, root: str, rel: str, size: str = "medium"):
-        try:
-            message_id_str, _ = rel.split('_', 1)
-            message_id = int(message_id_str)
-        except (ValueError, IndexError):
-            return None
-
-        try:
-            client = await self._get_connected_client()
-            message = await self._get_cached_message(message_id)
-            if not message:
-                return None
-
-            thumb = self._pick_photo_thumb(self._get_message_thumbs(message))
-            if not thumb:
-                return None
-
-            embedded = getattr(thumb, "bytes", None)
-            if embedded and isinstance(thumb, types.PhotoCachedSize):
-                return bytes(embedded)
-            if embedded and isinstance(thumb, types.PhotoStrippedSize):
-                return utils.stripped_photo_to_jpg(bytes(embedded))
-
-            async with self._download_lock:
-                result = await client.download_media(message, bytes, thumb=thumb)
-            if isinstance(result, (bytes, bytearray)):
-                return bytes(result)
-            return None
-        except Exception:
-            return None
+        return None
 
     async def delete(self, root: str, rel: str):
         """删除一个文件 (即一条消息)"""
@@ -625,11 +598,14 @@ class TelegramAdapter:
                     raise HTTPException(status_code=400, detail="Invalid Range header")
 
             headers["Content-Length"] = str(end - start + 1)
+            self._active_stream_message_id = message_id
 
             async def iterator():
                 downloaded = 0
                 try:
                     limit = end - start + 1
+                    if self._active_stream_message_id != message_id:
+                        return
                     async with self._download_lock:
                         async for chunk in client.iter_download(
                             media,
@@ -638,6 +614,8 @@ class TelegramAdapter:
                             chunk_size=self._download_chunk_size,
                             file_size=file_size,
                         ):
+                            if self._active_stream_message_id != message_id:
+                                return
                             if not chunk:
                                 continue
                             remaining = limit - downloaded
diff --git a/web/src/apps/PluginHost/index.tsx b/web/src/apps/PluginHost/index.tsx
index 78ef901..e549864 100644
--- a/web/src/apps/PluginHost/index.tsx
+++ b/web/src/apps/PluginHost/index.tsx
@@ -24,6 +24,16 @@ function getPluginStylePaths(plugin: PluginItem): string[] {
   return styles.filter((s) => typeof s === 'string' && s.trim().length > 0);
 }
 
+function unloadPluginFrame(iframe: HTMLIFrameElement | null) {
+  if (!iframe) return;
+  try {
+    iframe.contentWindow?.postMessage({ type: 'foxel-plugin:unload' }, window.location.origin);
+  } catch {
+    void 0;
+  }
+  iframe.src = 'about:blank';
+}
+
 /**
  * 插件宿主组件 - 文件打开模式
  * 使用 iframe 隔离渲染与样式，避免插件污染宿主 DOM/CSS。
@@ -66,7 +76,10 @@ export const PluginAppHost: React.FC<PluginAppHostProps> = ({
     };
 
     window.addEventListener('message', onMessage);
-    return () => window.removeEventListener('message', onMessage);
+    return () => {
+      window.removeEventListener('message', onMessage);
+      unloadPluginFrame(iframeRef.current);
+    };
   }, [plugin.key]);
 
   return (
@@ -118,7 +131,10 @@ export const PluginAppOpenHost: React.FC<PluginAppOpenHostProps> = ({ plugin, on
     };
 
     window.addEventListener('message', onMessage);
-    return () => window.removeEventListener('message', onMessage);
+    return () => {
+      window.removeEventListener('message', onMessage);
+      unloadPluginFrame(iframeRef.current);
+    };
   }, [plugin.key]);
 
   return (
diff --git a/web/src/plugin-frame.ts b/web/src/plugin-frame.ts
index 81f3ce5..f43e187 100644
--- a/web/src/plugin-frame.ts
+++ b/web/src/plugin-frame.ts
@@ -364,12 +364,27 @@ async function main() {
 
   await mountError();
 
-  window.addEventListener('beforeunload', () => {
+  const runCleanup = () => {
     try {
       cleanup?.();
     } catch {
       void 0;
     }
+    cleanup = null;
+  };
+
+  window.addEventListener('message', (ev) => {
+    if (ev.origin !== window.location.origin) return;
+    if (ev.source !== window.parent) return;
+    const data = ev.data as any;
+    if (!data || typeof data !== 'object') return;
+    if (data.type !== 'foxel-plugin:unload') return;
+    runCleanup();
+    root.innerHTML = '';
+  });
+
+  window.addEventListener('beforeunload', () => {
+    runCleanup();
   });
 }