产品/客户搜索改为输入框下方下拉列表，选中后阻止trace重复触发搜索

main.py

@@ -217,9 +217,11 @@ class App:
         r0 = Frame(fixed_frame)
         r0.pack(fill=X, pady=2)
         Label(r0, text="产品:", width=10, anchor="e").pack(side="left")
-        Entry(r0, textvariable=self.fv_product, width=20).pack(side="left", padx=5)
+        self.fv_product_entry = Entry(r0, textvariable=self.fv_product, width=20)
+        self.fv_product_entry.pack(side="left", padx=5)
         Label(r0, text="客户:", width=10, anchor="e").pack(side="left", padx=(30, 0))
-        Entry(r0, textvariable=self.fv_customer, width=20).pack(side="left", padx=5)
+        self.fv_customer_entry = Entry(r0, textvariable=self.fv_customer, width=20)
+        self.fv_customer_entry.pack(side="left", padx=5)
 
         # Row 1: 寄达地 | 无影响
         r1 = Frame(fixed_frame)
@@ -443,7 +445,7 @@ class App:
                 return
             names = [c.get("productName", "") for c in candidates]
             self._show_search_dropdown(
-                "选择产品", names,
+                self.fv_product_entry, names,
                 lambda idx: self._on_product_selected(candidates[idx]),
             )
         except Exception as e:
@@ -461,26 +463,28 @@ class App:
                 for c in candidates
             ]
             self._show_search_dropdown(
-                "选择客户", names,
+                self.fv_customer_entry, names,
                 lambda idx: self._on_customer_selected(candidates[idx]),
             )
         except Exception as e:
             self._log(f"[error] 客户搜索失败: {e}")
 
-    def _show_search_dropdown(self, title: str, options: list[str], on_select):
-        """在屏幕中央弹出下拉选择窗口。"""
+    def _show_search_dropdown(self, entry: Entry, options: list[str], on_select):
+        """在输入框正下方弹出下拉候选列表。"""
         popup = Toplevel(self.root)
-        popup.title(title)
-        popup.geometry("360x260")
-        popup.transient(self.root)
-        popup.grab_set()
+        popup.overrideredirect(True)
         popup.attributes("-topmost", True)
 
-        Label(popup, text=title, font=("", 10, "bold"), pady=6).pack()
+        # 定位在输入框正下方
+        x = entry.winfo_rootx()
+        y = entry.winfo_rooty() + entry.winfo_height()
+        w = entry.winfo_width()
+        popup.geometry(f"{w}x180+{x}+{y}")
 
-        frame = Frame(popup)
-        frame.pack(fill="both", expand=True, padx=10, pady=5)
-        listbox = Listbox(frame, font=("", 10))
+        frame = Frame(popup, bd=1, relief="solid")
+        frame.pack(fill="both", expand=True)
+
+        listbox = Listbox(frame, font=("", 10), selectmode="browse", activestyle="none")
         scroll = Scrollbar(frame, orient=VERTICAL, command=listbox.yview)
         listbox.configure(yscrollcommand=scroll.set)
         scroll.pack(side=RIGHT, fill=Y)
@@ -488,37 +492,35 @@ class App:
         for opt in options:
             listbox.insert(END, opt)
 
-        chosen = [False]
-
-        def select():
+        def select(e=None):
             sel = listbox.curselection()
             if sel:
-                chosen[0] = True
                 popup.destroy()
                 on_select(sel[0])
 
-        def cancel():
+        def cancel(e=None):
             popup.destroy()
 
-        listbox.bind("<Double-1>", lambda e: select())
-        listbox.bind("<Return>", lambda e: select())
-        listbox.bind("<Escape>", lambda e: cancel())
+        listbox.bind("<ButtonRelease-1>", select)
+        listbox.bind("<Return>", select)
+        listbox.bind("<Escape>", cancel)
         listbox.focus_set()
         if listbox.size() > 0:
             listbox.selection_set(0)
 
-        btn_f = Frame(popup)
-        btn_f.pack(pady=8)
-        Button(btn_f, text="选择", command=select, bg="#4CAF50", fg="white", width=8).pack(side=LEFT, padx=5)
-        Button(btn_f, text="取消", command=cancel, width=8).pack(side=LEFT, padx=5)
+        # 点击外部关闭
+        def on_focus_out(e):
+            popup.after(150, lambda: popup.destroy() if not popup.focus_get() else None)
+        popup.bind("<FocusOut>", on_focus_out)
 
-        popup.protocol("WM_DELETE_WINDOW", cancel)
         popup.wait_window()
 
     def _on_product_selected(self, choice: dict):
         """产品选中：缓存选择并获取详情。"""
         self._product_cached_choice = choice
+        self._loading_config = True  # 阻止 trace 再次触发搜索
         self.fv_product.set(choice.get("productName", ""))
+        self._loading_config = False
         # 获取产品详情
         try:
             biz_id = choice.get("productId", "")
@@ -532,7 +534,9 @@ class App:
     def _on_customer_selected(self, choice: dict):
         """客户选中：缓存选择并获取详情和寄件人实名。"""
         self._customer_cached_choice = choice
+        self._loading_config = True  # 阻止 trace 再次触发搜索
         self.fv_customer.set(choice.get("customerFullName", choice.get("customerName", "")))
+        self._loading_config = False
         # 获取客户详情
         try:
             cust_id = choice.get("customerId", "")