feat: UX overhaul with custom window chrome and single-instance support

src/CodingWithCalvin.VSToolbox/App.xaml

@@ -40,6 +40,64 @@
                 <Setter Property="Padding" Value="8"/>
                 <Setter Property="Opacity" Value="0.5"/>
             </Style>
+
+            <!-- Modern pill-style tab for RadioButton -->
+            <Style x:Key="PillTabStyle" TargetType="RadioButton">
+                <Setter Property="Background" Value="Transparent"/>
+                <Setter Property="Foreground" Value="{ThemeResource TextFillColorSecondaryBrush}"/>
+                <Setter Property="BorderThickness" Value="0"/>
+                <Setter Property="Padding" Value="12,8"/>
+                <Setter Property="MinWidth" Value="0"/>
+                <Setter Property="MinHeight" Value="0"/>
+                <Setter Property="CornerRadius" Value="6"/>
+                <Setter Property="Template">
+                    <Setter.Value>
+                        <ControlTemplate TargetType="RadioButton">
+                            <Grid x:Name="RootGrid">
+                                <Grid.RowDefinitions>
+                                    <RowDefinition Height="*"/>
+                                    <RowDefinition Height="Auto"/>
+                                </Grid.RowDefinitions>
+                                <VisualStateManager.VisualStateGroups>
+                                    <VisualStateGroup x:Name="CheckStates">
+                                        <VisualState x:Name="Checked">
+                                            <VisualState.Setters>
+                                                <Setter Target="ContentPresenter.Foreground" Value="{ThemeResource TextFillColorPrimaryBrush}"/>
+                                                <Setter Target="ActiveIndicator.Opacity" Value="1"/>
+                                            </VisualState.Setters>
+                                        </VisualState>
+                                        <VisualState x:Name="Unchecked"/>
+                                        <VisualState x:Name="Indeterminate"/>
+                                    </VisualStateGroup>
+                                </VisualStateManager.VisualStateGroups>
+                                <Border
+                                    x:Name="RootBorder"
+                                    Grid.Row="0"
+                                    Background="{TemplateBinding Background}"
+                                    CornerRadius="{TemplateBinding CornerRadius}"
+                                    Padding="{TemplateBinding Padding}">
+                                    <ContentPresenter
+                                        x:Name="ContentPresenter"
+                                        Content="{TemplateBinding Content}"
+                                        ContentTemplate="{TemplateBinding ContentTemplate}"
+                                        Foreground="{TemplateBinding Foreground}"
+                                        HorizontalAlignment="Center"
+                                        VerticalAlignment="Center"/>
+                                </Border>
+                                <!-- Active indicator bar -->
+                                <Border
+                                    x:Name="ActiveIndicator"
+                                    Grid.Row="1"
+                                    Height="3"
+                                    Margin="4,4,4,0"
+                                    CornerRadius="2"
+                                    Background="#68217A"
+                                    Opacity="0"/>
+                            </Grid>
+                        </ControlTemplate>
+                    </Setter.Value>
+                </Setter>
+            </Style>
         </ResourceDictionary>
     </Application.Resources>
 </Application>

src/CodingWithCalvin.VSToolbox/App.xaml.cs

@@ -1,4 +1,5 @@
 using System.Runtime.InteropServices;
+using System.Threading;
 using CodingWithCalvin.VSToolbox.Services;
 using Microsoft.UI;
 using Microsoft.UI.Windowing;
@@ -7,19 +8,83 @@
 
 namespace CodingWithCalvin.VSToolbox;
 
+// Windows API for setting window corner preference
+internal static class NativeMethods
+{
+    [DllImport("dwmapi.dll")]
+    internal static extern int DwmSetWindowAttribute(IntPtr hwnd, int attr, ref int attrValue, int attrSize);
+
+    [DllImport("user32.dll")]
+    internal static extern int GetWindowLong(IntPtr hwnd, int nIndex);
+
+    [DllImport("user32.dll")]
+    internal static extern int SetWindowLong(IntPtr hwnd, int nIndex, int dwNewLong);
+
+    [DllImport("user32.dll")]
+    internal static extern bool SetWindowPos(IntPtr hwnd, IntPtr hwndInsertAfter, int x, int y, int cx, int cy, uint uFlags);
+
+    internal const int DWMWA_WINDOW_CORNER_PREFERENCE = 33;
+    internal const int DWMWCP_DONOTROUND = 1;
+    internal const int DWMWA_CAPTION_COLOR = 35;
+    internal const int DWMWA_BORDER_COLOR = 34;
+
+    internal const int GWL_STYLE = -16;
+    internal const int WS_CAPTION = 0x00C00000;
+    internal const int WS_THICKFRAME = 0x00040000;
+    internal const uint SWP_FRAMECHANGED = 0x0020;
+    internal const uint SWP_NOMOVE = 0x0002;
+    internal const uint SWP_NOSIZE = 0x0001;
+    internal const uint SWP_NOZORDER = 0x0004;
+
+    // For finding and showing existing window
+    internal delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr lParam);
+
+    [DllImport("user32.dll")]
+    internal static extern bool EnumWindows(EnumWindowsProc lpEnumFunc, IntPtr lParam);
+
+    [DllImport("user32.dll", CharSet = CharSet.Unicode)]
+    internal static extern int GetWindowText(IntPtr hWnd, System.Text.StringBuilder lpString, int nMaxCount);
+
+    [DllImport("user32.dll")]
+    internal static extern bool IsWindowVisible(IntPtr hWnd);
+
+    [DllImport("user32.dll")]
+    internal static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
+
+    [DllImport("user32.dll")]
+    internal static extern bool SetForegroundWindow(IntPtr hWnd);
+
+    internal const int SW_RESTORE = 9;
+    internal const int SW_SHOW = 5;
+}
+
 public partial class App : Application
 {
+    private const string MutexName = "CodingWithCalvin.VSToolbox.SingleInstance";
+    private static Mutex? _mutex;
     private Window? _window;
     private AppWindow? _appWindow;
     private TrayIconService? _trayIconService;
 
+    public Window? MainWindow => _window;
+
     public App()
     {
         InitializeComponent();
     }
 
     protected override void OnLaunched(LaunchActivatedEventArgs e)
     {
+        // Check for single instance
+        _mutex = new Mutex(true, MutexName, out var createdNew);
+        if (!createdNew)
+        {
+            // Another instance is already running - try to bring it to front
+            BringExistingInstanceToFront();
+            Environment.Exit(0);
+            return;
+        }
+
         _window = new Window
         {
             Title = "Visual Studio Toolbox"
@@ -37,6 +102,9 @@ protected override void OnLaunched(LaunchActivatedEventArgs e)
             _appWindow.SetIcon(iconPath);
         }
 
+        // Configure custom title bar with square corners
+        ConfigureCustomTitleBar();
+
         // Set up the main content
         var rootFrame = new Frame();
         rootFrame.NavigationFailed += OnNavigationFailed;
@@ -57,6 +125,41 @@ protected override void OnLaunched(LaunchActivatedEventArgs e)
         _window.Activate();
     }
 
+    private void ConfigureCustomTitleBar()
+    {
+        if (_appWindow is null || _window is null) return;
+
+        // Get the window handle for native API calls
+        var hwnd = WinRT.Interop.WindowNative.GetWindowHandle(_window);
+
+        // Set square corners using DWM API
+        var cornerPreference = NativeMethods.DWMWCP_DONOTROUND;
+        NativeMethods.DwmSetWindowAttribute(hwnd, NativeMethods.DWMWA_WINDOW_CORNER_PREFERENCE,
+            ref cornerPreference, sizeof(int));
+
+        // Set caption and border color to purple (#68217A = 0x007A2168 in COLORREF BGR format)
+        var purpleColor = 0x007A2168; // BGR format for #68217A
+        NativeMethods.DwmSetWindowAttribute(hwnd, NativeMethods.DWMWA_CAPTION_COLOR,
+            ref purpleColor, sizeof(int));
+        NativeMethods.DwmSetWindowAttribute(hwnd, NativeMethods.DWMWA_BORDER_COLOR,
+            ref purpleColor, sizeof(int));
+
+        // Remove the caption from window style to eliminate the title bar area
+        var style = NativeMethods.GetWindowLong(hwnd, NativeMethods.GWL_STYLE);
+        style &= ~NativeMethods.WS_CAPTION; // Remove caption
+        NativeMethods.SetWindowLong(hwnd, NativeMethods.GWL_STYLE, style);
+        NativeMethods.SetWindowPos(hwnd, IntPtr.Zero, 0, 0, 0, 0,
+            NativeMethods.SWP_FRAMECHANGED | NativeMethods.SWP_NOMOVE | NativeMethods.SWP_NOSIZE | NativeMethods.SWP_NOZORDER);
+
+        // Make window borderless (no system title bar at all)
+        if (_appWindow.Presenter is OverlappedPresenter presenter)
+        {
+            presenter.SetBorderAndTitleBar(false, false);
+            presenter.IsResizable = true;
+            presenter.IsMaximizable = false;
+        }
+    }
+
     private void PositionWindowBottomRight(int width, int height)
     {
         if (_appWindow is null) return;
@@ -86,4 +189,29 @@ private void OnNavigationFailed(object sender, NavigationFailedEventArgs e)
     {
         throw new InvalidOperationException($"Failed to load Page {e.SourcePageType.FullName}");
     }
+
+    private static void BringExistingInstanceToFront()
+    {
+        const string windowTitle = "Visual Studio Toolbox";
+        IntPtr foundWindow = IntPtr.Zero;
+
+        NativeMethods.EnumWindows((hWnd, lParam) =>
+        {
+            var sb = new System.Text.StringBuilder(256);
+            NativeMethods.GetWindowText(hWnd, sb, sb.Capacity);
+            if (sb.ToString() == windowTitle)
+            {
+                foundWindow = hWnd;
+                return false; // Stop enumeration
+            }
+            return true; // Continue enumeration
+        }, IntPtr.Zero);
+
+        if (foundWindow != IntPtr.Zero)
+        {
+            // Show and bring the window to front
+            NativeMethods.ShowWindow(foundWindow, NativeMethods.SW_RESTORE);
+            NativeMethods.SetForegroundWindow(foundWindow);
+        }
+    }
 }