diff --git a/app.py b/app.py
index 593a239..d913790 100644
--- a/app.py
+++ b/app.py
@@ -20,7 +20,7 @@ from . import APP_NAME, DISPLAY_NAME, __version__
 from .config import PROVIDER_LABELS, AppConfig
 from .i18n import LANGUAGE_SHORT, LANGUAGES, get_language, on_language_changed, set_language, tr
 from .state import AppContext
-from .ui.widgets import widen_popup
+from .ui.widgets import tidy_popup
 from .theme import current_palette, set_active_theme, stylesheet
 from .core.task_scheduler import TaskScheduler
 from .ui.cowork_tab import CoworkTab
@@ -261,7 +261,7 @@ class MainWindow(QMainWindow):
         self.nav_project.setObjectName("navProjectPick")
         self.nav_project.setToolTip(tr("app.nav.project_pick"))
         self.nav_project.currentIndexChanged.connect(self._on_rail_project_pick)
-        widen_popup(self.nav_project)
+        tidy_popup(self.nav_project)
         self.nav_new_chat = QPushButton(tr("cowork.new_chat"))
         self.nav_new_chat.setObjectName("navNewChatBtn")
         self.nav_new_chat.setIcon(_icon("plus"))
@@ -675,7 +675,7 @@ class MainWindow(QMainWindow):
             if idx >= 0:
                 self.nav_project.setCurrentIndex(idx)
             has = bool(choices)
-            widen_popup(self.nav_project)
+            tidy_popup(self.nav_project)
             self.nav_project.setEnabled(has)
             self.nav_project_btn.setEnabled(has)
             self.nav_project_btn.setToolTip(
@@ -991,7 +991,7 @@ class MainWindow(QMainWindow):
         idx = self.language_combo.findData(get_language())
         if idx >= 0:
             self.language_combo.setCurrentIndex(idx)
-        widen_popup(self.language_combo)
+        tidy_popup(self.language_combo)
         self.language_combo.currentIndexChanged.connect(self._on_language_changed)
         who.addWidget(self.language_combo)
         self.theme_btn = self._build_theme_button()
@@ -1005,7 +1005,7 @@ class MainWindow(QMainWindow):
         self.provider_combo.setToolTip(tr("app.provider"))
         for key, label in PROVIDER_LABELS.items():
             self.provider_combo.addItem(label, key)
-        widen_popup(self.provider_combo)
+        tidy_popup(self.provider_combo)
         idx = self.provider_combo.findData(self.ctx.config.active_provider)
         if idx >= 0:
             self.provider_combo.setCurrentIndex(idx)
diff --git a/tools/check_combo_popup.py b/tools/check_combo_popup.py
index 5a61cd3..abd423a 100644
--- a/tools/check_combo_popup.py
+++ b/tools/check_combo_popup.py
@@ -50,6 +50,7 @@ def main() -> int:
     app.processEvents()
 
     fails = []
+    from PySide6.QtWidgets import QStyledItemDelegate
     for name in ("language_combo", "nav_project", "provider_combo"):
         combo = getattr(win, name, None)
         if combo is None or not combo.count():
@@ -66,6 +67,20 @@ def main() -> int:
         if have < need:
             fails.append(f"{name}: popup {have}px, khong du {need}px cho chu + dau tick")
 
+        # No tick: the row is already tinted, and the menu-style delegate that
+        # draws one on macOS covered the two letters it was marking.
+        deleg = combo.itemDelegate()
+        plain = type(deleg) is QStyledItemDelegate
+        print(f"{'':15}  delegate={type(deleg).__name__} (khong ve dau tick={plain})")
+        if not plain:
+            fails.append(f"{name}: dung delegate kieu menu — macOS se ve dau tick")
+
+        # ...and the current row must still be obvious without one.
+        view = combo.view()
+        sheet = app.styleSheet()
+        if "selection-background-color" not in sheet:
+            fails.append("popup khong to mau muc dang chon")
+
     print()
     for f in fails:
         print("FAIL  " + f)
diff --git a/ui/widgets.py b/ui/widgets.py
index 21e3234..cf85c3d 100644
--- a/ui/widgets.py
+++ b/ui/widgets.py
@@ -162,17 +162,25 @@ def guard_wheel(root: QWidget) -> None:
         w.installEventFilter(_wheel_guard)
 
 
-def widen_popup(combo) -> None:
-    """Give a drop-list room for its text AND the tick beside the current item.
+def tidy_popup(combo) -> None:
+    """Make a drop-list show its options and nothing else.
 
-    macOS draws a checkmark against the selected row; Windows does not. A combo
-    only as wide as "VN" therefore looked fine here and had its two letters
-    covered there. The popup inherits the combo's width unless told otherwise,
-    so measure what has to fit and say so.
+    Two platform habits to undo. macOS marks the current row with a checkmark,
+    drawn by the menu-style delegate a combo gets by default; the row is already
+    tinted by selection-background-color, so the tick says nothing twice and, in
+    a combo only as wide as "VN", covered the letters it was marking. Handing
+    the view a plain QStyledItemDelegate switches it to item-view painting,
+    where no such glyph exists.
+
+    And the popup inherits the combo's width unless told otherwise, which had
+    the project and provider names cut off here regardless of platform. So
+    measure the longest item — plus an indicator's worth of room, in case a
+    style still draws one — and set that as the view's minimum.
     """
-    from PySide6.QtWidgets import QStyle
+    from PySide6.QtWidgets import QStyle, QStyledItemDelegate
 
     view = combo.view()
+    combo.setItemDelegate(QStyledItemDelegate(combo))
     fm = view.fontMetrics()
     longest = max((fm.horizontalAdvance(combo.itemText(i))
                    for i in range(combo.count())), default=0)