diff --git a/gpui-app/Cargo.toml b/gpui-app/Cargo.toml
index ef38570..a09f2de 100644
--- a/gpui-app/Cargo.toml
+++ b/gpui-app/Cargo.toml
@@ -3,6 +3,7 @@ name = "mqttx-desktop"
 version = "1.0.0"
 edition.workspace = true
 description = "MQTT X —— 基于 GPUI 的跨平台 MQTT 调试客户端"
+license = "Apache-2.0"
 default-run = "mqttx"
 
 [[bin]]
diff --git a/gpui-app/src/aliyun.rs b/gpui-app/src/aliyun.rs
index a494a5c..9fcbef9 100644
--- a/gpui-app/src/aliyun.rs
+++ b/gpui-app/src/aliyun.rs
@@ -44,7 +44,9 @@ impl AliyunAuthMode {
     }
 }
 
-#[derive(Debug, Clone, Serialize, Deserialize)]
+// Debug 手写脱敏：AccessKeySecret 与 DeviceSecret 是长期凭据，一次 `{:?}` 格式化
+// 就会把它们送进 stderr 与 Sentry（panic 钩子会一并上报），因此不能 derive。
+#[derive(Clone, Serialize, Deserialize)]
 pub struct AliyunPreset {
     pub id: String,
     pub name: String,
@@ -152,6 +154,10 @@ impl AliyunPreset {
                 {
                     return Err("Group ID、AccessKey ID 与 AccessKey Secret 不能为空".into());
                 }
+                // 空 DeviceName 会拼出 "group@@@" 这样的非法 clientId，服务端报错难懂
+                if self.device_id.trim().is_empty() {
+                    return Err("Device ID 不能为空".into());
+                }
                 conn.host = self.host();
                 let client_id = format!("{}@@@{}", self.group_id, self.device_id);
                 let password = Self::signature(&self.access_key_secret, &client_id)?;
@@ -164,6 +170,10 @@ impl AliyunPreset {
                 if self.product_key.is_empty() || self.device_secret.is_empty() {
                     return Err("一机一密需要 ProductKey 与 DeviceSecret (设备密钥)".into());
                 }
+                // 空 DeviceName 会拼出 "pk.|securemode=..." 与 "&pk"，服务端报错难懂
+                if self.device_id.trim().is_empty() {
+                    return Err("一机一密需要 DeviceName（设备名）".into());
+                }
                 conn.host = self.host();
                 // 物联网平台「一机一密」直连三元组（见模块文档），DeviceName 复用 device_id
                 let device_name = self.device_id.trim();
@@ -189,3 +199,22 @@ impl Default for AliyunPreset {
         Self::new()
     }
 }
+
+impl std::fmt::Debug for AliyunPreset {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("AliyunPreset")
+            .field("id", &self.id)
+            .field("name", &self.name)
+            .field("group", &self.group)
+            .field("instance_id", &self.instance_id)
+            .field("region", &self.region)
+            .field("auth_mode", &self.auth_mode)
+            .field("access_key_id", &self.access_key_id)
+            .field("access_key_secret", &"<redacted>")
+            .field("group_id", &self.group_id)
+            .field("device_id", &self.device_id)
+            .field("product_key", &self.product_key)
+            .field("device_secret", &"<redacted>")
+            .finish()
+    }
+}
diff --git a/gpui-app/src/ui/app/linear-theme.json b/gpui-app/src/ui/app/linear-theme.json
index f5b6966..6656f1f 100644
--- a/gpui-app/src/ui/app/linear-theme.json
+++ b/gpui-app/src/ui/app/linear-theme.json
@@ -3,9 +3,9 @@
     {
       "name": "Linear Light",
       "mode": "light",
-      "font_size": 14,
+      "font.size": 14,
       "radius": 6,
-      "radius_lg": 10,
+      "radius.lg": 10,
       "colors": {
         "accent.background": "#eeeef0",
         "accent.foreground": "#0d0e10",
@@ -211,9 +211,9 @@
     {
       "name": "Linear Dark",
       "mode": "dark",
-      "font_size": 14,
+      "font.size": 14,
       "radius": 6,
-      "radius_lg": 10,
+      "radius.lg": 10,
       "colors": {
         "accent.background": "#1c1d1f",
         "accent.foreground": "#f7f8f8",
diff --git a/gpui-app/src/ui/app/titlebar.rs b/gpui-app/src/ui/app/titlebar.rs
index 2704ad7..c5637ba 100644
--- a/gpui-app/src/ui/app/titlebar.rs
+++ b/gpui-app/src/ui/app/titlebar.rs
@@ -14,6 +14,38 @@ use super::*;
 impl MqttXApp {
 pub(super) fn render_titlebar(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
         let app_weak = cx.entity().downgrade();
+        // 非 Windows 平台 `set_topmost` 恒为 false，渲染一个必然报错的按钮只会让人困惑
+        let pin_button = if cfg!(target_os = "windows") {
+            Some(
+                Button::new("pin-window")
+                    .icon(if self.pinned {
+                        IconName::PinOff
+                    } else {
+                        IconName::Pin
+                    })
+                    .ghost()
+                    .small()
+                    .tooltip(if self.pinned {
+                        "取消窗口置顶"
+                    } else {
+                        "窗口置顶"
+                    })
+                    .on_click(cx.listener(|this, _, window, cx| {
+                        let next = !this.pinned;
+                        if crate::platform::set_topmost(window, next) {
+                            this.pinned = next;
+                            cx.notify();
+                        } else {
+                            window.push_notification(
+                                Notification::error("置顶操作失败"),
+                                cx,
+                            );
+                        }
+                    })),
+            )
+        } else {
+            None
+        };
 
         TitleBar::new().child(
             h_flex()
@@ -59,33 +91,7 @@ pub(super) fn render_titlebar(&mut self, _window: &mut Window, cx: &mut Context<
                                     this.open_connection_form(None, window, cx);
                                 })),
                         )
-                        .child(
-                            Button::new("pin-window")
-                                .icon(if self.pinned {
-                                    IconName::PinOff
-                                } else {
-                                    IconName::Pin
-                                })
-                                .ghost()
-                                .small()
-                                .tooltip(if self.pinned {
-                                    "取消窗口置顶"
-                                } else {
-                                    "窗口置顶"
-                                })
-                                .on_click(cx.listener(|this, _, window, cx| {
-                                    let next = !this.pinned;
-                                    if crate::platform::set_topmost(window, next) {
-                                        this.pinned = next;
-                                        cx.notify();
-                                    } else {
-                                        window.push_notification(
-                                            Notification::error("置顶操作失败"),
-                                            cx,
-                                        );
-                                    }
-                                })),
-                        )
+                        .children(pin_button)
                         .child(self.render_theme_toggle(cx))
                         .child(
                             Button::new("more-menu")
diff --git a/gpui-app/src/ui/connection_form.rs b/gpui-app/src/ui/connection_form.rs
index c02b894..47afbf5 100644
--- a/gpui-app/src/ui/connection_form.rs
+++ b/gpui-app/src/ui/connection_form.rs
@@ -6,7 +6,7 @@ use std::sync::Arc;
 
 use gpui_kit::component::scroll::ScrollableElement as _;
 use gpui_kit::component::button::{Button, ButtonVariants as _};
-use gpui_kit::component::input::{Input, InputState};
+use gpui_kit::component::input::{Input, InputEvent, InputState};
 use gpui_kit::component::select::{Select, SelectEvent, SelectState};
 use gpui_kit::component::switch::Switch;
 use gpui_kit::component::{
@@ -240,7 +240,9 @@ impl ConnectionForm {
         // 切换传输方式时，把端口同步成该方式的默认端口，并刷新 WS 路径的按需显示。
         // gpui 列表点击任意项（含当前项）都会发 Confirm，若不比对索引，
         // 打开下拉点一下当前传输就会把自定义端口静默改回默认值。
-        let last_transport = std::cell::Cell::new(transport_idx);
+        // 记录"上一个传输方式"而非索引：端口只在仍是上一个方式的默认端口时才跟随，
+        // 与全部默认端口比较会把用户恰好手输的 8084/8883 等值误判为默认值而覆盖
+        let last_transport = std::cell::Cell::new(TransportKind::ALL[transport_idx]);
         let port_for_sub = port.clone();
         let sub_transport = cx.subscribe_in(
             &transport,
@@ -250,17 +252,15 @@ impl ConnectionForm {
                     && let Some(idx) = state.read(cx).selected_value().copied()
                     && let Some(kind) = TransportKind::ALL.get(idx).copied()
                 {
-                    // 索引未变化：视为重新点选当前项，不覆盖用户输入的端口
-                    if last_transport.get() == idx {
+                    // 未变化：视为重新点选当前项，不覆盖用户输入的端口
+                    if last_transport.get() == kind {
                         return;
                     }
-                    // 端口只在仍是某个默认端口（而非用户自定义值）时才跟随切换：
-                    // 否则 WSS:9443 → TCP → WSS 的往返会把 9443 静默丢失
-                    let current = port_for_sub.read(cx).value().trim().parse::<u16>().ok();
-                    let is_default = matches!(current, Some(p) if
-                        TransportKind::ALL.iter().any(|k| k.default_port() == p));
-                    last_transport.set(idx);
-                    if is_default {
+                    // WSS:9443 → TCP → WSS 的往返不会丢失 9443
+                    let is_prev_default = port_for_sub.read(cx).value().trim().parse::<u16>().ok()
+                        == Some(last_transport.get().default_port());
+                    last_transport.set(kind);
+                    if is_prev_default {
                         port_for_sub.update(cx, |p, cx| {
                             p.set_value(kind.default_port().to_string(), window, cx);
                         });
@@ -290,6 +290,42 @@ impl ConnectionForm {
             || c.maximum_packet_size.is_some()
             || c.topic_alias_maximum.is_some();
 
+        // 任一被校验字段被编辑时清空字段错误：错误只在保存/测试时登记，若不随输入
+        // 清除，用户改好值后红字仍然挂着，无从判断当前输入是否已合法
+        let err_watch: [Entity<InputState>; 16] = [
+            name.clone(),
+            host.clone(),
+            port.clone(),
+            path.clone(),
+            client_id.clone(),
+            keep_alive.clone(),
+            conn_timeout.clone(),
+            max_reconnect.clone(),
+            session_expiry.clone(),
+            receive_max.clone(),
+            max_packet.clone(),
+            topic_alias.clone(),
+            ssl_ca.clone(),
+            ssl_client_cert.clone(),
+            ssl_client_key.clone(),
+            will_topic.clone(),
+        ];
+        let mut err_subs = Vec::with_capacity(err_watch.len());
+        for w in err_watch {
+            err_subs.push(cx.subscribe_in(
+                &w,
+                window,
+                move |this, _, ev: &InputEvent, _, cx| {
+                    if matches!(ev, InputEvent::Change)
+                        && !this.field_errors.borrow().is_empty()
+                    {
+                        this.field_errors.borrow_mut().clear();
+                        cx.notify();
+                    }
+                },
+            ));
+        }
+
         Self {
             engine,
             editing_id,
@@ -334,7 +370,11 @@ impl ConnectionForm {
             show_ssl: ssl_configured,
             field_errors: RefCell::default(),
             testing: false,
-            _subs: vec![sub_transport, sub_protocol],
+            _subs: {
+                let mut subs = vec![sub_transport, sub_protocol];
+                subs.extend(err_subs);
+                subs
+            },
         }
     }
 
@@ -364,6 +404,25 @@ impl ConnectionForm {
             .map_err(|_| format!("{label} 需要是 0~65535 的整数"))
     }
 
+    /// 端口：1~65535。0 不是可连接端口，放行只会在 CONNECT 阶段报出难以理解的错误。
+    fn parse_port(s: &str) -> Result<u16, String> {
+        match s.trim().parse::<u16>() {
+            Ok(0) => Err("端口需要是 1~65535 的整数".into()),
+            Ok(p) => Ok(p),
+            Err(_) => Err("端口需要是 1~65535 的整数".into()),
+        }
+    }
+
+    /// 同 `parse_opt_u32`，但 0 视为非法：MQTT 5 规范把 Receive Maximum /
+    /// Maximum Packet Size 为 0 定义为 Protocol Error，broker 会直接断开连接，
+    /// 且该值会被持久化，表现为"每次连接都失败"。
+    fn parse_opt_positive_u32(s: &str, label: &str) -> Result<Option<u32>, String> {
+        match Self::parse_opt_u32(s, label)? {
+            Some(0) => Err(format!("{label} 必须大于 0（0 是 MQTT 5 协议错误）")),
+            other => Ok(other),
+        }
+    }
+
     fn parse_opt_u32(s: &str, label: &str) -> Result<Option<u32>, String> {
         let s = s.trim();
         if s.is_empty() {
@@ -402,7 +461,7 @@ impl ConnectionForm {
             return Err(self.fail("host", "主机地址不能为空"));
         }
         let host = host.trim().to_string();
-        let port = self.fail_as("port", Self::parse_u16(&self.val(&self.port, cx), "端口"))?;
+        let port = self.fail_as("port", Self::parse_port(&self.val(&self.port, cx)))?;
         let mut client_id = self.val(&self.client_id, cx);
         if client_id.trim().is_empty() {
             if !for_test {
@@ -429,16 +488,16 @@ impl ConnectionForm {
             }
         };
         let receive_maximum = self.fail_as("receive_max", (|| -> Result<_, String> {
-            Ok(Self::parse_opt_u32(&self.val(&self.receive_max, cx), "接收上限")?
+            Ok(Self::parse_opt_positive_u32(&self.val(&self.receive_max, cx), "接收上限")?
                 .map(|v| u16::try_from(v).map_err(|_| "接收上限不能超过 65535".to_string()))
                 .transpose())
         })())??;
         let maximum_packet_size = self.fail_as(
             "max_packet",
-            Self::parse_opt_u32(&self.val(&self.max_packet, cx), "最大报文长度"),
+            Self::parse_opt_positive_u32(&self.val(&self.max_packet, cx), "最大报文长度"),
         )?;
         let topic_alias_maximum = self.fail_as("topic_alias", (|| -> Result<_, String> {
-            Ok(Self::parse_opt_u32(&self.val(&self.topic_alias, cx), "主题别名")?
+            Ok(Self::parse_opt_positive_u32(&self.val(&self.topic_alias, cx), "主题别名")?
                 .map(|v| u16::try_from(v).map_err(|_| "主题别名上限不能超过 65535".to_string()))
                 .transpose())
         })())??;
@@ -528,10 +587,18 @@ impl ConnectionForm {
         }
 
         let last_will = if self.will_enabled {
-            let topic = self.val(&self.will_topic, cx);
-            if topic.trim().is_empty() {
+            // 与其它字段一致：trim 后入库
+            let topic = self.val(&self.will_topic, cx).trim().to_string();
+            if topic.is_empty() {
                 return Err(self.fail("will_topic", "遗嘱主题不能为空"));
             }
+            // 通配符只用于订阅过滤器；出现在 PUBLISH 主题上会被 broker 直接拒绝
+            if topic.contains('+') || topic.contains('#') {
+                return Err(self.fail(
+                    "will_topic",
+                    "遗嘱主题不能包含通配符 + 或 #",
+                ));
+            }
             let opt_str = |v: String| {
                 let t = v.trim().to_string();
                 if t.is_empty() { None } else { Some(t) }
diff --git a/gpui-app/src/ui/dialogs/aliyun_dialog.rs b/gpui-app/src/ui/dialogs/aliyun_dialog.rs
index 6a694af..64d3b70 100644
--- a/gpui-app/src/ui/dialogs/aliyun_dialog.rs
+++ b/gpui-app/src/ui/dialogs/aliyun_dialog.rs
@@ -52,10 +52,13 @@ macro_rules! text_field {
 impl AliyunDialog {
     fn new(app: Entity<MqttXApp>, presets: Vec<AliyunPreset>, window: &mut Window, cx: &mut Context<Self>) -> Self {
         let first = presets.first().cloned().unwrap_or_else(AliyunPreset::new);
+        // 表单已用 first 预填：selected 也指向它，否则"打开即保存"会用相同的
+        // 内容 push 出一条重复预设（selected=None 走新建分支、另生成 uuid）
+        let selected = (!presets.is_empty()).then_some(0);
         Self {
             app,
             presets,
-            selected: None,
+            selected,
             name: text_field!(cx, window, &first.name, "预设名称"),
             group: text_field!(cx, window, &first.group, "分组（可选）"),
             instance_id: text_field!(cx, window, &first.instance_id, "post-cn-xxxx"),
@@ -365,6 +368,11 @@ impl Render for AliyunDialog {
 }
 
 pub fn open(app: Entity<MqttXApp>, window: &mut Window, cx: &mut App) {
+    // 对话框是栈式叠加：标题栏菜单、快捷键、行内按钮等多个入口都会调 open，
+    // 不加守卫会压入第二个模态，同 id 的控件在两层之间串台
+    if window.has_active_dialog(cx) {
+        return;
+    }
     let presets = app.read(cx).aliyun_presets.clone();
     let dialog_view = cx.new(|cx| AliyunDialog::new(app, presets, window, cx));
     window.open_dialog(cx, move |dialog, _, _| {
diff --git a/gpui-app/src/ui/dialogs/presets_dialog.rs b/gpui-app/src/ui/dialogs/presets_dialog.rs
index bbf59f7..742ea8c 100644
--- a/gpui-app/src/ui/dialogs/presets_dialog.rs
+++ b/gpui-app/src/ui/dialogs/presets_dialog.rs
@@ -558,6 +558,11 @@ impl Render for PresetsDialog {
 }
 
 pub fn open(app: Entity<MqttXApp>, window: &mut Window, cx: &mut App) {
+    // 对话框是栈式叠加：标题栏菜单、快捷键、行内按钮等多个入口都会调 open，
+    // 不加守卫会压入第二个模态，同 id 的控件在两层之间串台
+    if window.has_active_dialog(cx) {
+        return;
+    }
     let presets = app.read(cx).presets.clone();
     let dialog_view: Entity<PresetsDialog> =
         cx.new(|cx| PresetsDialog::new(app, presets, window, cx));
diff --git a/gpui-app/src/ui/dialogs/resource_dialog.rs b/gpui-app/src/ui/dialogs/resource_dialog.rs
index cbe224a..eb2de99 100644
--- a/gpui-app/src/ui/dialogs/resource_dialog.rs
+++ b/gpui-app/src/ui/dialogs/resource_dialog.rs
@@ -470,6 +470,11 @@ impl Render for ResourceMonitorDialog {
 }
 
 pub fn open(app: Entity<MqttXApp>, window: &mut Window, cx: &mut App) {
+    // 对话框是栈式叠加：标题栏菜单、快捷键、行内按钮等多个入口都会调 open，
+    // 不加守卫会压入第二个模态，同 id 的控件在两层之间串台
+    if window.has_active_dialog(cx) {
+        return;
+    }
     let dialog_view = cx.new(|cx| ResourceMonitorDialog::new(app, cx));
     // 用弱引用刷新：对话框关闭、实体释放后 update 返回 Err，循环退出。
     // 强引用的 update 在实体释放后会 panic。
diff --git a/gpui-app/src/ui/dialogs/variables_dialog.rs b/gpui-app/src/ui/dialogs/variables_dialog.rs
index 67e8c9d..63e1216 100644
--- a/gpui-app/src/ui/dialogs/variables_dialog.rs
+++ b/gpui-app/src/ui/dialogs/variables_dialog.rs
@@ -11,6 +11,11 @@ use crate::ui::app::MqttXApp;
 use crate::ui::widgets::KvEditor;
 
 pub fn open(app: Entity<MqttXApp>, window: &mut Window, cx: &mut App) {
+    // 对话框是栈式叠加：标题栏菜单、快捷键、行内按钮等多个入口都会调 open，
+    // 不加守卫会压入第二个模态，同 id 的控件在两层之间串台
+    if window.has_active_dialog(cx) {
+        return;
+    }
     let pairs: Vec<(String, String)> = app
         .read(cx)
         .variables
diff --git a/gpui-app/src/ui/widgets/select.rs b/gpui-app/src/ui/widgets/select.rs
index 7b6d9c3..518e605 100644
--- a/gpui-app/src/ui/widgets/select.rs
+++ b/gpui-app/src/ui/widgets/select.rs
@@ -49,13 +49,17 @@ impl SearchableListDelegate for OptionDelegate {
     fn item(&self, ix: IndexPath) -> Option<&Self::Item> {
         self.items.get(ix.row)
     }
-    fn position<V>(&self, _value: &V) -> Option<IndexPath>
+    fn position<V>(&self, value: &V) -> Option<IndexPath>
     where
         Self::Item: SearchableListItem<Value = V>,
         V: PartialEq,
     {
-        // 选中项统一通过 IndexPath 构造，无需按值反查
-        None
+        // 框架契约：按值反查索引，set_selected_value 与过滤视图都依赖它。
+        // 返回 None 会导致下拉显示空、保存写默认值，这里必须如实实现。
+        self.items
+            .iter()
+            .position(|i| i.value() == value)
+            .map(IndexPath::new)
     }
 }