Refactor error handling, DPI scaling, and UI events

- Replace custom error UI with Logger.LogError for exceptions
- Remove acrylic backdrop; use semi-transparent black background
- Scale IdentifyWindow size for DPI using GetDpiForWindow
- Remove ValueChanged handlers from sliders; use PointerCaptureLost
- Delete unused event handlers and clean up using directives
- Simplify input source switching logic in MainWindow

src/modules/powerdisplay/PowerDisplay/PowerDisplayXAML/App.xaml.cs

@@ -10,8 +10,6 @@ using Microsoft.PowerToys.Settings.UI.Library;
 using Microsoft.PowerToys.Telemetry;
 using Microsoft.UI.Dispatching;
 using Microsoft.UI.Xaml;
-using Microsoft.UI.Xaml.Controls;
-using Microsoft.UI.Xaml.Media;
 using Microsoft.Windows.AppLifecycle;
 using PowerDisplay.Helpers;
 using PowerDisplay.Serialization;
@@ -75,11 +73,7 @@ namespace PowerDisplay
         /// </summary>
         private void OnUnhandledException(object sender, Microsoft.UI.Xaml.UnhandledExceptionEventArgs e)
         {
-            // Try to display error information
+            Logger.LogError("Unhandled exception", e.Exception);
-            ShowStartupError(e.Exception);
-
-            // Mark exception as handled to prevent app crash
-            e.Handled = true;
         }
 
         /// <summary>
@@ -196,7 +190,7 @@ namespace PowerDisplay
             }
             catch (Exception ex)
             {
-                ShowStartupError(ex);
+                Logger.LogError("PowerDisplay startup failed", ex);
             }
         }
 
@@ -260,66 +254,6 @@ namespace PowerDisplay
                 CancellationToken.None);
         }
 
-        /// <summary>
-        /// Show startup error
-        /// </summary>
-        private void ShowStartupError(Exception ex)
-        {
-            try
-            {
-                Logger.LogError($"PowerDisplay startup failed: {ex.Message}");
-
-                var errorWindow = new Window { Title = "PowerDisplay - Startup Error" };
-                var panel = new StackPanel { Margin = new Thickness(20), Spacing = 16 };
-
-                panel.Children.Add(new TextBlock
-                {
-                    Text = "PowerDisplay Startup Failed",
-                    FontSize = 20,
-                    FontWeight = Microsoft.UI.Text.FontWeights.SemiBold,
-                });
-
-                panel.Children.Add(new TextBlock
-                {
-                    Text = $"Error: {ex.Message}",
-                    FontSize = 14,
-                    TextWrapping = TextWrapping.Wrap,
-                });
-
-                panel.Children.Add(new TextBlock
-                {
-                    Text = $"Details:\n{ex}",
-                    FontSize = 12,
-                    TextWrapping = TextWrapping.Wrap,
-                    Foreground = new SolidColorBrush(Microsoft.UI.Colors.Gray),
-                    Margin = new Thickness(0, 10, 0, 0),
-                });
-
-                var closeButton = new Button
-                {
-                    Content = "Close",
-                    HorizontalAlignment = HorizontalAlignment.Right,
-                    Margin = new Thickness(0, 10, 0, 0),
-                };
-                closeButton.Click += (_, _) => errorWindow.Close();
-                panel.Children.Add(closeButton);
-
-                errorWindow.Content = new ScrollViewer
-                {
-                    Content = panel,
-                    VerticalScrollBarVisibility = ScrollBarVisibility.Auto,
-                    MaxHeight = 600,
-                    MaxWidth = 800,
-                };
-
-                errorWindow.Activate();
-            }
-            catch
-            {
-                Environment.Exit(1);
-            }
-        }
-
         /// <summary>
         /// Gets the main window instance
         /// </summary>

src/modules/powerdisplay/PowerDisplay/PowerDisplayXAML/IdentifyWindow.xaml

@@ -1,11 +1,11 @@
-<Window
+<Window
     x:Class="PowerDisplay.PowerDisplayXAML.IdentifyWindow"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     mc:Ignorable="d">
-    <Grid Background="Transparent">
+    <Grid Background="#1A000000">
         <TextBlock
             x:Name="NumberText"
             HorizontalAlignment="Center"

src/modules/powerdisplay/PowerDisplay/PowerDisplayXAML/IdentifyWindow.xaml.cs

@@ -4,9 +4,9 @@
 
 using System;
 using System.Globalization;
+using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using Microsoft.UI;
-using Microsoft.UI.Composition.SystemBackdrops;
 using Microsoft.UI.Windowing;
 using Microsoft.UI.Xaml;
 using PowerDisplay.Helpers;
@@ -18,12 +18,17 @@ namespace PowerDisplay.PowerDisplayXAML
     /// <summary>
     /// Interaction logic for IdentifyWindow.xaml
     /// </summary>
-    public sealed partial class IdentifyWindow : Window, IDisposable
+    public sealed partial class IdentifyWindow : Window
     {
+        // Window size in device-independent units (DIU)
+        private const int WindowWidthDiu = 300;
+        private const int WindowHeightDiu = 280;
+
         private AppWindow? _appWindow;
-        private DesktopAcrylicController? _acrylicController;
+        private double _dpiScale = 1.0;
-        private SystemBackdropConfiguration? _configurationSource;
+
-        private bool _disposed;
+        [LibraryImport("user32.dll")]
+        private static partial uint GetDpiForWindow(IntPtr hwnd);
 
         public IdentifyWindow(int number)
         {
@@ -49,6 +54,9 @@ namespace PowerDisplay.PowerDisplayXAML
             var windowId = Win32Interop.GetWindowIdFromWindow(hwnd);
             _appWindow = AppWindow.GetFromWindowId(windowId);
 
+            // Get DPI scale for this window
+            _dpiScale = GetDpiForWindow(hwnd) / 96.0;
+
             if (_appWindow != null)
             {
                 // Remove title bar using OverlappedPresenter
@@ -61,38 +69,17 @@ namespace PowerDisplay.PowerDisplayXAML
                     presenter.IsMaximizable = false;
                 }
 
-                // Set window size to fit the large number (200pt font)
+                // Set window size scaled for DPI
-                _appWindow.Resize(new SizeInt32 { Width = 300, Height = 280 });
+                // AppWindow.Resize expects physical pixels
+                int physicalWidth = (int)(WindowWidthDiu * _dpiScale);
+                int physicalHeight = (int)(WindowHeightDiu * _dpiScale);
+                _appWindow.Resize(new SizeInt32 { Width = physicalWidth, Height = physicalHeight });
             }
 
             // Set window topmost and hide from taskbar
             WindowHelper.SetWindowTopmost(hwnd, true);
             WindowHelper.HideFromTaskbar(hwnd);
             WindowHelper.DisableWindowMovingAndResizing(hwnd);
-
-            // Configure 90% transparent acrylic backdrop
-            ConfigureAcrylicBackdrop();
-        }
-
-        private void ConfigureAcrylicBackdrop()
-        {
-            if (!DesktopAcrylicController.IsSupported())
-            {
-                return;
-            }
-
-            _configurationSource = new SystemBackdropConfiguration();
-            _acrylicController = new DesktopAcrylicController();
-
-            // Set 90% transparency (TintOpacity 0.1 = 10% tint = 90% transparent)
-            _acrylicController.TintColor = Windows.UI.Color.FromArgb(255, 0, 0, 0);
-            _acrylicController.TintOpacity = 0.1f;
-            _acrylicController.LuminosityOpacity = 0f;
-
-            // Add target using WinRT cast
-            var target = WinRT.CastExtensions.As<Microsoft.UI.Composition.ICompositionSupportsSystemBackdrop>(this);
-            _acrylicController.AddSystemBackdropTarget(target);
-            _acrylicController.SetSystemBackdropConfiguration(_configurationSource);
         }
 
         /// <summary>
@@ -106,26 +93,16 @@ namespace PowerDisplay.PowerDisplayXAML
             }
 
             var workArea = displayArea.WorkArea;
-            int windowWidth = 300;
+
-            int windowHeight = 280;
+            // Window size in physical pixels (already scaled for DPI)
+            int physicalWidth = (int)(WindowWidthDiu * _dpiScale);
+            int physicalHeight = (int)(WindowHeightDiu * _dpiScale);
 
             // Calculate center position (WorkArea coordinates are in physical pixels)
-            int x = workArea.X + ((workArea.Width - windowWidth) / 2);
+            int x = workArea.X + ((workArea.Width - physicalWidth) / 2);
-            int y = workArea.Y + ((workArea.Height - windowHeight) / 2);
+            int y = workArea.Y + ((workArea.Height - physicalHeight) / 2);
 
             _appWindow.Move(new PointInt32(x, y));
         }
-
-        public void Dispose()
-        {
-            if (_disposed)
-            {
-                return;
-            }
-
-            _disposed = true;
-            _acrylicController?.Dispose();
-            _acrylicController = null;
-        }
     }
 }

src/modules/powerdisplay/PowerDisplay/PowerDisplayXAML/MainWindow.xaml

@@ -193,7 +193,6 @@
                                                         Minimum="{x:Bind MinBrightness, Mode=OneWay}"
                                                         PointerCaptureLost="Slider_PointerCaptureLost"
                                                         Tag="Brightness"
-                                                        ValueChanged="Slider_ValueChanged"
                                                         Value="{x:Bind Brightness, Mode=OneWay}" />
                                                 </Grid>
 
@@ -226,7 +225,6 @@
                                                         Minimum="0"
                                                         PointerCaptureLost="Slider_PointerCaptureLost"
                                                         Tag="Contrast"
-                                                        ValueChanged="Slider_ValueChanged"
                                                         Value="{x:Bind ContrastPercent, Mode=OneWay}" />
                                                 </Grid>
 
@@ -260,7 +258,6 @@
                                                         Minimum="{x:Bind MinVolume, Mode=OneWay}"
                                                         PointerCaptureLost="Slider_PointerCaptureLost"
                                                         Tag="Volume"
-                                                        ValueChanged="Slider_ValueChanged"
                                                         Value="{x:Bind Volume, Mode=OneWay}" />
                                                 </Grid>
 

src/modules/powerdisplay/PowerDisplay/PowerDisplayXAML/MainWindow.xaml.cs

@@ -9,12 +9,9 @@ using System.Threading.Tasks;
 using ManagedCommon;
 using Microsoft.PowerToys.Settings.UI.Library;
 using Microsoft.UI;
-using Microsoft.UI.Composition;
 using Microsoft.UI.Windowing;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
-using Microsoft.UI.Xaml.Media;
-using Microsoft.UI.Xaml.Media.Animation;
 using PowerDisplay.Common.Models;
 using PowerDisplay.Configuration;
 using PowerDisplay.Helpers;
@@ -602,17 +599,6 @@ namespace PowerDisplay
             }
         }
 
-        /// <summary>
-        /// Slider ValueChanged event handler - does nothing during drag
-        /// This allows the slider UI to update smoothly without triggering hardware operations
-        /// </summary>
-        private void Slider_ValueChanged(object sender, Microsoft.UI.Xaml.Controls.Primitives.RangeBaseValueChangedEventArgs e)
-        {
-            // During drag, this event fires 60-120 times per second
-            // We intentionally do nothing here to keep UI smooth
-            // The actual ViewModel update happens in PointerCaptureLost after drag completes
-        }
-
         /// <summary>
         /// Slider PointerCaptureLost event handler - updates ViewModel when drag completes
         /// This is the WinUI3 recommended way to detect drag completion
@@ -663,75 +649,6 @@ namespace PowerDisplay
             Logger.LogDebug($"[UI] ViewModel property {propertyName} updated successfully");
         }
 
-        /// <summary>
-        /// Input source item click handler - switches the monitor input source
-        /// </summary>
-        private async void InputSourceItem_Click(object sender, RoutedEventArgs e)
-        {
-            Logger.LogInfo("[UI] InputSourceItem_Click: Event triggered!");
-
-            if (sender is not Button button)
-            {
-                Logger.LogWarning("[UI] InputSourceItem_Click: sender is not Button");
-                return;
-            }
-
-            Logger.LogInfo($"[UI] InputSourceItem_Click: Button clicked, Tag type = {button.Tag?.GetType().Name ?? "null"}, DataContext type = {button.DataContext?.GetType().Name ?? "null"}");
-
-            // Get the InputSourceItem from Tag (not DataContext - Flyout doesn't inherit DataContext properly)
-            var inputSourceItem = button.Tag as InputSourceItem;
-            if (inputSourceItem == null)
-            {
-                Logger.LogWarning("[UI] InputSourceItem_Click: Tag is not InputSourceItem");
-                return;
-            }
-
-            Logger.LogInfo($"[UI] InputSourceItem_Click: InputSourceItem found - Value=0x{inputSourceItem.Value:X2}, Name={inputSourceItem.Name}, MonitorId={inputSourceItem.MonitorId}");
-
-            int inputSourceValue = inputSourceItem.Value;
-            string monitorId = inputSourceItem.MonitorId;
-
-            // Use MonitorId for direct lookup (Flyout popup is not in visual tree)
-            MonitorViewModel? monitorVm = null;
-
-            if (!string.IsNullOrEmpty(monitorId) && _viewModel != null)
-            {
-                monitorVm = _viewModel.Monitors.FirstOrDefault(m => m.Id == monitorId);
-                Logger.LogInfo($"[UI] InputSourceItem_Click: Found MonitorViewModel by ID: {monitorVm?.Name ?? "null"}");
-            }
-
-            // Fallback: search through all monitors (for backwards compatibility)
-            if (monitorVm == null && _viewModel != null)
-            {
-                Logger.LogInfo("[UI] InputSourceItem_Click: MonitorId lookup failed, trying fallback search");
-                foreach (var vm in _viewModel.Monitors)
-                {
-                    if (vm.SupportsInputSource && vm.AvailableInputSources != null)
-                    {
-                        if (vm.AvailableInputSources.Any(s => s.Value == inputSourceValue))
-                        {
-                            monitorVm = vm;
-                            Logger.LogInfo($"[UI] InputSourceItem_Click: Found MonitorViewModel by fallback: {vm.Name}");
-                            break;
-                        }
-                    }
-                }
-            }
-
-            if (monitorVm == null)
-            {
-                Logger.LogWarning("[UI] InputSourceItem_Click: Could not find MonitorViewModel");
-                return;
-            }
-
-            Logger.LogInfo($"[UI] Switching input source for {monitorVm.Name} to 0x{inputSourceValue:X2} ({inputSourceItem.Name})");
-
-            // Set the input source
-            await monitorVm.SetInputSourceAsync(inputSourceValue);
-
-            Logger.LogInfo("[UI] InputSourceItem_Click: SetInputSourceAsync completed");
-        }
-
         /// <summary>
         /// Input source ListView selection changed handler - switches the monitor input source
         /// </summary>
@@ -766,13 +683,6 @@ namespace PowerDisplay
 
             // Set the input source
             await monitorVm.SetInputSourceAsync(selectedItem.Value);
-
-            // Close the flyout after selection
-            if (listView.Parent is StackPanel stackPanel &&
-                stackPanel.Parent is Flyout flyout)
-            {
-                flyout.Hide();
-            }
         }
 
         /// <summary>