diff --git a/WebRTCControllerWeb/src/components/ConnectionPanel.vue b/WebRTCControllerWeb/src/components/ConnectionPanel.vue
index 4467c44..8c31f7d 100644
--- a/WebRTCControllerWeb/src/components/ConnectionPanel.vue
+++ b/WebRTCControllerWeb/src/components/ConnectionPanel.vue
@@ -52,7 +52,7 @@ function onConnectDevice() {
     </div>
 
     <button class="btn" @click="onConnectDevice" :disabled="!selected || store.rtcConnected">发起远程控制</button>
-    <button class="btn danger" v-if="store.rtcConnected" @click="disconnectDevice">结束控制</button>
+    <button class="btn danger" style="margin-top:12px" v-if="store.rtcConnected" @click="disconnectDevice">结束控制</button>
 
     <div v-if="store.error" class="error">{{ store.error }}</div>
 
diff --git a/WebRTCControllerWeb/src/services/SignalingClient.js b/WebRTCControllerWeb/src/services/SignalingClient.js
index 17e9568..f696fe6 100644
--- a/WebRTCControllerWeb/src/services/SignalingClient.js
+++ b/WebRTCControllerWeb/src/services/SignalingClient.js
@@ -34,8 +34,15 @@ export class SignalingClient {
         // 记录关闭码和原因，便于诊断断连根因：
         // 1000 = 正常关闭, 1001 = 离开, 1006 = 异常断开（无 close frame）
         // 1009 = 消息过大, 1011 = 服务端异常
-        console.warn('[信令] WebSocket 已关闭 code=%d reason=%s wasClean=%s',
-          ev.code, ev.reason || '(无)', ev.wasClean);
+        let hint = '';
+        if (ev.code === 1009) {
+          // 关闭帧由服务端发出：服务端 WebSocket 单条消息缓冲上限过小，
+          // 导致 SDP/ICE 等稍大的消息被拒绝。需在信令服务端调大消息大小上限
+          // （Spring 原生 WebSocket 用 configureWebSocketTransport#setMessageSizeLimit）。
+          hint = '（消息过大：请检查信令服务端 WebSocket 的 messageSizeLimit 配置是否过小）';
+        }
+        console.warn('[信令] WebSocket 已关闭 code=%d reason=%s wasClean=%s%s',
+          ev.code, ev.reason || '(无)', ev.wasClean, hint);
         this._stopHeartbeat();
         this.onDisconnected && this.onDisconnected(ev.code, ev.reason);
       };