Usage popup closes on any click elsewhere; no black corners behind popups

src/CCWrapper/Views/BottomBar.xaml

@@ -41,7 +41,7 @@
                 <TextBlock x:Name="CtxText" />
             </StackPanel>
             <Border Style="{StaticResource Sep}" />
-            <!-- ClickMode=Press: the click that closes the StaysOpen=false popup is the same mouse-down the 250 ms guard measures. A Button: it takes Win32 focus off the terminal's WebView2 when clicked, and has an automation peer for screen readers. -->
+            <!-- ClickMode=Press: the click that closes the popup is the same mouse-down the 250 ms guard measures. A Button: it takes Win32 focus off the terminal's WebView2 when clicked, and has an automation peer for screen readers. -->
             <Button x:Name="UsageGroup" Style="{StaticResource Chip}" Padding="6,0" Margin="0" ToolTipOpening="OnUsageTip"
                     AutomationProperties.Name="Plan usage details" ClickMode="Press" GotKeyboardFocus="OnUsageFocus" Click="OnUsageClick">
                 <StackPanel Orientation="Horizontal">
@@ -53,9 +53,11 @@
                     <TextBlock x:Name="WeekText" MinWidth="28" />
                 </StackPanel>
             </Button>
-            <!-- A Popup is its own window, so it may sit over the terminal's WebView2. Not inside UsageGroup: clicks in it would bubble to the toggle. -->
-            <Popup x:Name="UsagePopup" PlacementTarget="{Binding ElementName=UsageGroup}" Placement="Top" StaysOpen="False" Closed="OnUsageClosed">
-                <Border x:Name="UsagePanel" Style="{StaticResource UsagePanel}" Focusable="True" PreviewKeyDown="OnUsageKey">
+            <!-- A Popup is its own window, so it may sit over the terminal's WebView2. Not inside UsageGroup: clicks in it would bubble to the toggle.
+                 StaysOpen=True: StaysOpen=False's mouse capture closed it only on clicks in other apps, not on clicks elsewhere in this window; the code closes it (OnWindowMouseDown, OnUsageFocusWithin).
+                 AllowsTransparency: else the popup window paints black behind the rounded corners. -->
+            <Popup x:Name="UsagePopup" PlacementTarget="{Binding ElementName=UsageGroup}" Placement="Top" StaysOpen="True" AllowsTransparency="True" Closed="OnUsageClosed">
+                <Border x:Name="UsagePanel" Style="{StaticResource UsagePanel}" Focusable="True" PreviewKeyDown="OnUsageKey" IsKeyboardFocusWithinChanged="OnUsageFocusWithin">
                     <StackPanel x:Name="UsageBody" />
                 </Border>
             </Popup>

src/CCWrapper/Views/BottomBar.xaml.cs

@@ -30,6 +30,7 @@ public partial class BottomBar : UserControl
     (double? Five, double? Week, DateTimeOffset? FiveReset, DateTimeOffset? WeekReset) _usageNow;
     DateTime _usageClosedAt;
     IInputElement? _usageFocus; // what had focus before the usage button took it, for Esc to give back
+    Window? _window;
     CompactPrefs _compact = CompactPrefs.Load();
     readonly DispatcherTimer _usageTimer = new() { Interval = TimeSpan.FromMinutes(30) };
 
@@ -48,6 +49,13 @@ public BottomBar()
             CompactPrefs.Saved += OnCompactPrefs;
             OnCompactPrefs();
             _usageTimer.Start();
+            if ((_window = Window.GetWindow(this)) is { } w)
+            {
+                w.PreviewMouseDown += OnWindowMouseDown;
+                w.Deactivated += CloseUsage;
+                w.LocationChanged += CloseUsage;
+                w.SizeChanged += CloseUsage;
+            }
             await ReadAccountAsync();
             await CheckUsageAsync(force: false); // skipped when the start screen just checked
         };
@@ -57,6 +65,13 @@ public BottomBar()
             AppUpdate.Changed -= ShowUpdate;
             CompactPrefs.Saved -= OnCompactPrefs;
             _usageTimer.Stop();
+            if (_window is { } w)
+            {
+                w.PreviewMouseDown -= OnWindowMouseDown;
+                w.Deactivated -= CloseUsage;
+                w.LocationChanged -= CloseUsage;
+                w.SizeChanged -= CloseUsage;
+            }
         };
         _ = new SessionFollower<BarSource, BarData>(this, s => new BarSource(s), r => r.Read(), async d =>
         {
@@ -109,9 +124,17 @@ void Render()
     // Built when it opens: the "in 2h 10m" of the reset times is relative to now, not to the last render.
     void OnUsageTip(object sender, ToolTipEventArgs e) => UsageGroup.ToolTip = _usageTip();
 
-    // StaysOpen=false closes the popup on the mouse-down of a click on the button itself, so a click right after a close must not reopen it.
+    // OnWindowMouseDown closes the popup on the mouse-down of a click on the button itself, so a click right after a close must not reopen it.
     void OnUsageClick(object sender, RoutedEventArgs e) => OpenUsage();
 
+    // Any press in this window but in the popup closes it. The popup's own mouse events route through the window too. A click in a
+    // WebView2 (terminal, Browser panel) never reaches WPF: it takes the focus, and OnUsageFocusWithin closes the popup then.
+    void OnWindowMouseDown(object sender, MouseButtonEventArgs e) { if (!UsagePanel.IsMouseOver) CloseUsage(sender, e); }
+
+    void OnUsageFocusWithin(object sender, DependencyPropertyChangedEventArgs e) { if (!UsagePanel.IsKeyboardFocusWithin) UsagePopup.IsOpen = false; }
+
+    void CloseUsage(object? sender, EventArgs e) => UsagePopup.IsOpen = false;
+
     void OpenUsage()
     {
         if (UsagePopup.IsOpen || DateTime.UtcNow - _usageClosedAt < TimeSpan.FromMilliseconds(250)) return;

src/CCWrapper/Views/ComposeBox.xaml

@@ -42,8 +42,8 @@
                     </Style>
                 </TextBlock.Style>
             </TextBlock>
-            <!-- A Popup is its own window, so it may sit over the terminal's WebView2 -->
-            <Popup x:Name="SlashPopup" PlacementTarget="{Binding ElementName=Input}" Placement="Top" StaysOpen="True">
+            <!-- A Popup is its own window, so it may sit over the terminal's WebView2. AllowsTransparency: else it paints black behind the rounded corners. -->
+            <Popup x:Name="SlashPopup" PlacementTarget="{Binding ElementName=Input}" Placement="Top" StaysOpen="True" AllowsTransparency="True">
                 <Border Background="{StaticResource Panel}" BorderBrush="{StaticResource ControlLine}" BorderThickness="1" CornerRadius="8"
                         Width="{Binding ActualWidth, ElementName=Input}" Margin="0,0,0,4">
                     <ListBox x:Name="SlashList" MaxHeight="280" Focusable="False" Background="Transparent" BorderThickness="0"