Add host activity and DB browser, and keep dialogs, drag-drop, and idle maintenance responsive.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/Explorer.App/DatabaseWindow.xaml

@@ -0,0 +1,78 @@
+<Window x:Class="Explorer.App.DatabaseWindow"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        Title="Database"
+        Icon="pack://application:,,,/Assets/explorer-workbench.ico"
+        Height="720" Width="1100"
+        MinHeight="480" MinWidth="800"
+        WindowStartupLocation="CenterOwner"
+        Background="{DynamicResource Bg}" Foreground="{DynamicResource Fg}">
+  <DockPanel Margin="12">
+    <DockPanel DockPanel.Dock="Bottom" Margin="0,10,0,0">
+      <Button DockPanel.Dock="Right" Content="Close" MinWidth="88" Height="30" Click="OnClose" Margin="8,0,0,0"/>
+      <TextBlock Text="{Binding Status}" VerticalAlignment="Center" Foreground="{DynamicResource FgMuted}"
+                 TextTrimming="CharacterEllipsis"/>
+    </DockPanel>
+
+    <DockPanel DockPanel.Dock="Top" Margin="0,0,0,8">
+      <Button DockPanel.Dock="Right" Content="Close DB" MinWidth="80" Height="28"
+              Command="{Binding CloseDatabaseCommand}" Margin="6,0,0,0"/>
+      <Button DockPanel.Dock="Right" Content="Open file…" MinWidth="90" Height="28"
+              Click="OnOpenFile" Margin="6,0,0,0"/>
+      <Button DockPanel.Dock="Right" Content="Open Workbench index" MinWidth="150" Height="28"
+              Command="{Binding OpenWorkbenchIndexCommand}" Margin="6,0,0,0"/>
+      <StackPanel>
+        <TextBlock Text="{Binding PathLabel}" FontWeight="SemiBold" TextTrimming="CharacterEllipsis"/>
+        <TextBlock Text="{Binding ModeLabel}" Foreground="{DynamicResource FgMuted}" FontSize="11"/>
+      </StackPanel>
+    </DockPanel>
+
+    <Grid>
+      <Grid.ColumnDefinitions>
+        <ColumnDefinition Width="220"/>
+        <ColumnDefinition Width="8"/>
+        <ColumnDefinition Width="*"/>
+      </Grid.ColumnDefinitions>
+      <DockPanel>
+        <DockPanel DockPanel.Dock="Top" Margin="0,0,0,6">
+          <Button DockPanel.Dock="Right" Content="↻" Width="28" Height="26"
+                  Command="{Binding RefreshTablesCommand}" ToolTip="Refresh tables"/>
+          <TextBlock Text="Tables" FontWeight="SemiBold" VerticalAlignment="Center"/>
+        </DockPanel>
+        <ListBox ItemsSource="{Binding Tables}" SelectedItem="{Binding SelectedTable}"/>
+      </DockPanel>
+
+      <DockPanel Grid.Column="2">
+        <DockPanel DockPanel.Dock="Top" Margin="0,0,0,8">
+          <Button DockPanel.Dock="Right" Content="Run SQL" MinWidth="80" Height="28"
+                  Command="{Binding RunSqlCommand}" Margin="8,0,0,0"/>
+          <TextBox Text="{Binding Sql, UpdateSourceTrigger=PropertyChanged}" AcceptsReturn="True"
+                   Height="56" TextWrapping="Wrap" VerticalScrollBarVisibility="Auto"
+                   FontFamily="Consolas"/>
+        </DockPanel>
+        <DockPanel DockPanel.Dock="Top" Margin="0,0,0,8">
+          <TextBlock DockPanel.Dock="Left" Text="{Binding PageLabel}" VerticalAlignment="Center"
+                     Foreground="{DynamicResource FgMuted}" Margin="0,0,12,0"/>
+          <Button DockPanel.Dock="Left" Content="Prev" MinWidth="60" Height="26"
+                  Command="{Binding PrevPageCommand}" Margin="0,0,6,0"/>
+          <Button DockPanel.Dock="Left" Content="Next" MinWidth="60" Height="26"
+                  Command="{Binding NextPageCommand}" Margin="0,0,12,0"/>
+          <Button DockPanel.Dock="Left" Content="Edit cell…" MinWidth="80" Height="26"
+                  Click="OnEditCell" IsEnabled="{Binding CanWrite}" Margin="0,0,6,0"/>
+          <Button DockPanel.Dock="Left" Content="Insert row…" MinWidth="90" Height="26"
+                  Click="OnInsertRow" IsEnabled="{Binding CanWrite}" Margin="0,0,6,0"/>
+          <Button DockPanel.Dock="Left" Content="Delete row" MinWidth="80" Height="26"
+                  Command="{Binding DeleteSelectedRowCommand}" IsEnabled="{Binding CanWrite}"/>
+        </DockPanel>
+        <ListView x:Name="GridViewHost"
+                  ItemsSource="{Binding Rows}"
+                  SelectedItem="{Binding SelectedRow}"
+                  MouseDoubleClick="OnRowDoubleClick">
+          <ListView.View>
+            <GridView x:Name="ResultGrid"/>
+          </ListView.View>
+        </ListView>
+      </DockPanel>
+    </Grid>
+  </DockPanel>
+</Window>

src/Explorer.App/DatabaseWindow.xaml.cs

@@ -0,0 +1,159 @@
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Data;
+using System.Windows.Input;
+using Explorer.Presentation.ViewModels;
+using Microsoft.Win32;
+
+namespace Explorer.App;
+
+public partial class DatabaseWindow : Window
+{
+    public DatabaseWindow(DatabaseViewerViewModel vm)
+    {
+        InitializeComponent();
+        DataContext = vm;
+        ViewModel = vm;
+        vm.GridChanged += (_, _) => RebuildColumns();
+        ModelessWindowClose.EnableEscape(this);
+        Closed += async (_, _) => await vm.DisposeAsync().ConfigureAwait(true);
+        Loaded += async (_, _) => await vm.OpenIndexAsync(preferWrite: false).ConfigureAwait(true);
+    }
+
+    public DatabaseViewerViewModel ViewModel { get; }
+
+    private void OnClose(object sender, RoutedEventArgs e) => Close();
+
+    private void RebuildColumns()
+    {
+        ResultGrid.Columns.Clear();
+        for (var i = 0; i < ViewModel.Columns.Count; i++)
+        {
+            var index = i;
+            var header = ViewModel.Columns[i];
+            ResultGrid.Columns.Add(new GridViewColumn
+            {
+                Header = header,
+                Width = header.Equals("_rowid_", StringComparison.OrdinalIgnoreCase) ? 70 : 140,
+                DisplayMemberBinding = new Binding($"Cells[{index}]")
+            });
+        }
+    }
+
+    private void OnOpenFile(object sender, RoutedEventArgs e)
+    {
+        var dlg = new OpenFileDialog
+        {
+            Title = "Open SQLite database",
+            Filter = "SQLite databases (*.db;*.sqlite;*.sqlite3)|*.db;*.sqlite;*.sqlite3|All files (*.*)|*.*"
+        };
+        if (dlg.ShowDialog(this) == true)
+        {
+            var write = MessageBox.Show(
+                this,
+                "Open for writing? Choose No for read-only.",
+                "Database",
+                MessageBoxButton.YesNoCancel,
+                MessageBoxImage.Question);
+            if (write == MessageBoxResult.Cancel)
+            {
+                return;
+            }
+
+            _ = ViewModel.OpenPathAsync(dlg.FileName, preferWrite: write == MessageBoxResult.Yes);
+        }
+    }
+
+    private async void OnEditCell(object sender, RoutedEventArgs e)
+        => await EditSelectedCellAsync().ConfigureAwait(true);
+
+    private async void OnRowDoubleClick(object sender, MouseButtonEventArgs e)
+        => await EditSelectedCellAsync().ConfigureAwait(true);
+
+    private async Task EditSelectedCellAsync()
+    {
+        if (!ViewModel.CanWrite || ViewModel.SelectedRow is null || string.IsNullOrWhiteSpace(ViewModel.SelectedTable))
+        {
+            return;
+        }
+
+        var columns = ViewModel.EditableColumns();
+        if (columns.Count == 0)
+        {
+            return;
+        }
+
+        var column = Prompt("Column to edit", string.Join(", ", columns.Take(8)) + (columns.Count > 8 ? "…" : ""), columns[0]);
+        if (column is null || !columns.Contains(column, StringComparer.OrdinalIgnoreCase))
+        {
+            return;
+        }
+
+        var index = ViewModel.Columns.ToList().FindIndex(c => c.Equals(column, StringComparison.OrdinalIgnoreCase));
+        var current = index >= 0 && index < ViewModel.SelectedRow.Cells.Count
+            ? ViewModel.SelectedRow.Cells[index]
+            : "";
+        var next = Prompt("New value for " + column, "Leave empty for NULL.", current);
+        if (next is null)
+        {
+            return;
+        }
+
+        try
+        {
+            await ViewModel.UpdateSelectedCellAsync(column, string.IsNullOrEmpty(next) ? null : next)
+                .ConfigureAwait(true);
+        }
+        catch (Exception ex)
+        {
+            MessageBox.Show(this, ex.Message, "Database", MessageBoxButton.OK, MessageBoxImage.Warning);
+        }
+    }
+
+    private async void OnInsertRow(object sender, RoutedEventArgs e)
+    {
+        if (!ViewModel.CanWrite || string.IsNullOrWhiteSpace(ViewModel.SelectedTable))
+        {
+            return;
+        }
+
+        var columns = ViewModel.EditableColumns();
+        if (columns.Count == 0)
+        {
+            MessageBox.Show(this, "Load a table first so columns are known.", "Database");
+            return;
+        }
+
+        var values = new Dictionary<string, object?>(StringComparer.OrdinalIgnoreCase);
+        foreach (var column in columns)
+        {
+            var value = Prompt("Value for " + column, "Cancel skips this column. Empty = NULL.", "");
+            if (value is null)
+            {
+                continue;
+            }
+
+            values[column] = string.IsNullOrEmpty(value) ? null : value;
+        }
+
+        if (values.Count == 0)
+        {
+            return;
+        }
+
+        try
+        {
+            await ViewModel.InsertRowAsync(values).ConfigureAwait(true);
+        }
+        catch (Exception ex)
+        {
+            MessageBox.Show(this, ex.Message, "Database", MessageBoxButton.OK, MessageBoxImage.Warning);
+        }
+    }
+
+    private string? Prompt(string title, string message, string initial)
+    {
+        var dlg = new PromptWindow(title, message, initial) { Owner = this };
+        return dlg.ShowDialog() == true ? dlg.Value : null;
+    }
+}

src/Explorer.App/DocumentationWindow.xaml

@@ -9,9 +9,9 @@
         Background="{DynamicResource Bg}" Foreground="{DynamicResource Fg}">
   <DockPanel>
     <DockPanel DockPanel.Dock="Bottom" Margin="16,8,16,16">
-      <Button DockPanel.Dock="Right" Content="Close" MinWidth="88" Height="32" IsCancel="True" Margin="8,0,0,0"/>
+      <Button DockPanel.Dock="Right" Content="Close" MinWidth="88" Height="32" Click="OnClose" Margin="8,0,0,0"/>
       <Button DockPanel.Dock="Right" Content="Open file" MinWidth="88" Height="32" Click="OnOpenFile"
-              x:Name="OpenFileButton" Margin="8,0,0,0"/>
+              x:Name="OpenFileButton" IsEnabled="False" Margin="8,0,0,0"/>
       <Button DockPanel.Dock="Right" Content="Reload" MinWidth="88" Height="32" Click="OnReload" Margin="8,0,0,0"/>
       <TextBlock x:Name="SourceLabel" VerticalAlignment="Center" TextWrapping="Wrap"
                  Foreground="{DynamicResource FgMuted}"/>

src/Explorer.App/DocumentationWindow.xaml.cs

@@ -11,14 +11,19 @@ public partial class DocumentationWindow : Window
 {
     private FlowDocument? _document;
     private bool _suppressToc;
+    private int _renderGeneration;
 
     public DocumentationWindow()
     {
         InitializeComponent();
-        Loaded += (_, _) => Render();
+        ModelessWindowClose.EnableEscape(this);
+        Loaded += async (_, _) => await RenderAsync().ConfigureAwait(true);
     }
 
-    private void OnReload(object sender, RoutedEventArgs e) => Render();
+    private void OnClose(object sender, RoutedEventArgs e) => Close();
+
+    private async void OnReload(object sender, RoutedEventArgs e)
+        => await RenderAsync().ConfigureAwait(true);
 
     private void OnOpenFile(object sender, RoutedEventArgs e)
     {
@@ -44,10 +49,35 @@ public partial class DocumentationWindow : Window
         }
     }
 
-    private void Render()
+    private async Task RenderAsync()
     {
-        var loaded = DocumentationLoader.Load();
-        var parsed = MarkdownParser.Parse(loaded.Markdown);
+        var generation = Interlocked.Increment(ref _renderGeneration);
+        SourceLabel.Text = "Loading…";
+        LoadedDocumentation loaded;
+        MarkdownDocument parsed;
+        try
+        {
+            (loaded, parsed) = await Task.Run(() =>
+            {
+                var document = DocumentationLoader.Load();
+                return (document, MarkdownParser.Parse(document.Markdown));
+            }).ConfigureAwait(true);
+        }
+        catch (Exception ex)
+        {
+            if (generation == _renderGeneration)
+            {
+                SourceLabel.Text = "Could not load documentation: " + ex.Message;
+            }
+
+            return;
+        }
+
+        if (generation != _renderGeneration || !IsLoaded)
+        {
+            return;
+        }
+
         var brushes = new DocumentationBrushes(
             Brush("Fg"),
             Brush("FgMuted"),

src/Explorer.App/GitChangesWindow.xaml

@@ -9,7 +9,7 @@
         Background="{DynamicResource Bg}" Foreground="{DynamicResource Fg}">
   <DockPanel Margin="16">
     <DockPanel DockPanel.Dock="Bottom" Margin="0,12,0,0">
-      <Button DockPanel.Dock="Right" Content="Close" MinWidth="88" Height="32" IsCancel="True" Margin="8,0,0,0"/>
+      <Button DockPanel.Dock="Right" Content="Close" MinWidth="88" Height="32" Click="OnClose" Margin="8,0,0,0"/>
       <Button DockPanel.Dock="Right" Content="Commit…" MinWidth="88" Height="32"
               Click="OnCommit" IsEnabled="{Binding CanCommit}" Margin="8,0,0,0"/>
       <Button DockPanel.Dock="Right" Content="Push" MinWidth="72" Height="32"

src/Explorer.App/GitChangesWindow.xaml.cs

@@ -12,10 +12,13 @@ public partial class GitChangesWindow : Window
         InitializeComponent();
         DataContext = vm;
         ViewModel = vm;
+        ModelessWindowClose.EnableEscape(this);
     }
 
     public GitChangesViewModel ViewModel { get; }
 
+    private void OnClose(object sender, RoutedEventArgs e) => Close();
+
     private async void OnRowDoubleClick(object sender, MouseButtonEventArgs e)
         => await ShowDiffAsync().ConfigureAwait(true);
 

src/Explorer.App/GitDiffWindow.xaml

@@ -9,7 +9,7 @@
         Background="{DynamicResource Bg}" Foreground="{DynamicResource Fg}">
   <DockPanel Margin="16">
     <Button DockPanel.Dock="Bottom" Content="Close" MinWidth="88" Height="32" HorizontalAlignment="Right"
-            IsCancel="True" Margin="0,12,0,0"/>
+            Click="OnClose" Margin="0,12,0,0"/>
     <TextBlock DockPanel.Dock="Top" Text="{Binding EmptyText}" Margin="0,0,0,8"
                Foreground="{DynamicResource FgMuted}" TextWrapping="Wrap"
                Visibility="{Binding ShowEmpty, Converter={StaticResource BoolVis}}"/>

src/Explorer.App/GitDiffWindow.xaml.cs

@@ -10,5 +10,8 @@ public partial class GitDiffWindow : Window
         InitializeComponent();
         DataContext = vm;
         Title = vm.Title;
+        ModelessWindowClose.EnableEscape(this);
     }
+
+    private void OnClose(object sender, RoutedEventArgs e) => Close();
 }

src/Explorer.App/HostActivityMonitorWindow.xaml

@@ -0,0 +1,130 @@
+<Window x:Class="Explorer.App.HostActivityMonitorWindow"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:shell="clr-namespace:System.Windows.Shell;assembly=PresentationFramework"
+        Title="Host activity"
+        Icon="pack://application:,,,/Assets/explorer-workbench.ico"
+        Height="640" Width="960"
+        MinHeight="420" MinWidth="720"
+        WindowStartupLocation="CenterOwner"
+        WindowStyle="None"
+        ResizeMode="CanResize"
+        Background="{DynamicResource Bg}"
+        Foreground="{DynamicResource Fg}"
+        UseLayoutRounding="True"
+        SnapsToDevicePixels="True">
+  <shell:WindowChrome.WindowChrome>
+    <shell:WindowChrome CaptionHeight="40"
+                        ResizeBorderThickness="6"
+                        GlassFrameThickness="0"
+                        CornerRadius="0"
+                        UseAeroCaptionButtons="False"/>
+  </shell:WindowChrome.WindowChrome>
+  <DockPanel>
+    <Border DockPanel.Dock="Top" Height="40" Background="{DynamicResource Panel}"
+            BorderBrush="{DynamicResource Stroke}" BorderThickness="0,0,0,1"
+            MouseLeftButtonDown="OnTitleBarMouseDown">
+      <Grid>
+        <StackPanel Orientation="Horizontal" VerticalAlignment="Center" Margin="12,0,0,0" IsHitTestVisible="False">
+          <Image Width="20" Height="20" Margin="0,0,8,0" VerticalAlignment="Center"
+                 RenderOptions.BitmapScalingMode="HighQuality"
+                 Source="pack://application:,,,/Assets/explorer-workbench-20.png"/>
+          <TextBlock Text="Host activity" FontWeight="SemiBold" VerticalAlignment="Center"
+                     Foreground="{DynamicResource Fg}"/>
+        </StackPanel>
+        <StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
+          <Button Style="{StaticResource CaptionButton}" Content="─" Click="OnMinimize" ToolTip="Minimize"/>
+          <Button x:Name="MaxRestoreButton" Style="{StaticResource CaptionButton}" Content="☐"
+                  Click="OnMaxRestore" ToolTip="Maximize"/>
+          <Button Style="{StaticResource CaptionCloseButton}" Content="✕" Click="OnClose" ToolTip="Close"/>
+        </StackPanel>
+      </Grid>
+    </Border>
+
+    <DockPanel Margin="14">
+      <DockPanel DockPanel.Dock="Bottom" Margin="0,10,0,0">
+        <Button DockPanel.Dock="Right" Content="Close" MinWidth="88" Height="30" Click="OnClose" Margin="8,0,0,0"/>
+        <Button DockPanel.Dock="Right" Content="Run maintenance now" MinWidth="140" Height="30"
+                Command="{Binding RunMaintenanceNowCommand}" Margin="8,0,0,0"/>
+        <Button DockPanel.Dock="Right" Content="Refresh" MinWidth="88" Height="30"
+                Command="{Binding RefreshCommand}" Margin="8,0,0,0"/>
+        <TextBlock VerticalAlignment="Center" Foreground="{DynamicResource FgMuted}">
+          <Run Text="{Binding Status, Mode=OneWay}"/>
+          <Run Text="  ·  "/>
+          <Run Text="{Binding IsLive, Mode=OneWay, StringFormat=Live: {0}}"/>
+        </TextBlock>
+      </DockPanel>
+
+      <TextBlock DockPanel.Dock="Top" Text="{Binding Summary}" FontWeight="SemiBold" FontSize="15"
+                 TextWrapping="Wrap" Margin="0,0,0,10"/>
+
+      <UniformGrid DockPanel.Dock="Top" Rows="2" Columns="2" Margin="0,0,0,10">
+        <Border BorderBrush="{DynamicResource Stroke}" BorderThickness="1" Padding="10" Margin="0,0,6,6">
+          <StackPanel>
+            <TextBlock Text="Maintenance" Foreground="{DynamicResource FgMuted}" FontSize="11"/>
+            <TextBlock Text="{Binding MaintenanceText}" TextWrapping="Wrap" Margin="0,4,0,0"/>
+          </StackPanel>
+        </Border>
+        <Border BorderBrush="{DynamicResource Stroke}" BorderThickness="1" Padding="10" Margin="6,0,0,6">
+          <StackPanel>
+            <TextBlock Text="Indexing" Foreground="{DynamicResource FgMuted}" FontSize="11"/>
+            <TextBlock Text="{Binding IndexingText}" TextWrapping="Wrap" Margin="0,4,0,0"/>
+          </StackPanel>
+        </Border>
+        <Border BorderBrush="{DynamicResource Stroke}" BorderThickness="1" Padding="10" Margin="0,6,6,0">
+          <StackPanel>
+            <TextBlock Text="Hashing" Foreground="{DynamicResource FgMuted}" FontSize="11"/>
+            <TextBlock Text="{Binding HashText}" TextWrapping="Wrap" Margin="0,4,0,0"/>
+          </StackPanel>
+        </Border>
+        <Border BorderBrush="{DynamicResource Stroke}" BorderThickness="1" Padding="10" Margin="6,6,0,0">
+          <StackPanel>
+            <TextBlock Text="Transfers" Foreground="{DynamicResource FgMuted}" FontSize="11"/>
+            <TextBlock Text="{Binding TransferText}" TextWrapping="Wrap" Margin="0,4,0,0"/>
+          </StackPanel>
+        </Border>
+      </UniformGrid>
+
+      <Grid>
+        <Grid.ColumnDefinitions>
+          <ColumnDefinition Width="280"/>
+          <ColumnDefinition Width="10"/>
+          <ColumnDefinition Width="*"/>
+        </Grid.ColumnDefinitions>
+        <DockPanel>
+          <TextBlock DockPanel.Dock="Top" Text="Current indexing jobs" FontWeight="SemiBold" Margin="0,0,0,6"/>
+          <ListView ItemsSource="{Binding Jobs}" BorderBrush="{DynamicResource Stroke}"
+                    ScrollViewer.VerticalScrollBarVisibility="Auto"
+                    ScrollViewer.HorizontalScrollBarVisibility="Disabled">
+            <ListView.ItemTemplate>
+              <DataTemplate>
+                <StackPanel Margin="0,2">
+                  <TextBlock Text="{Binding Title}" FontWeight="SemiBold"/>
+                  <TextBlock Text="{Binding Detail}" Foreground="{DynamicResource FgMuted}" TextTrimming="CharacterEllipsis"/>
+                  <TextBlock Text="{Binding Origin}" Foreground="{DynamicResource FgMuted}" FontSize="11"/>
+                </StackPanel>
+              </DataTemplate>
+            </ListView.ItemTemplate>
+          </ListView>
+        </DockPanel>
+        <DockPanel Grid.Column="2">
+          <TextBlock DockPanel.Dock="Top" Text="{Binding LogCaption}" FontWeight="SemiBold" Margin="0,0,0,6"/>
+          <ListView x:Name="EventList" ItemsSource="{Binding Events}" BorderBrush="{DynamicResource Stroke}"
+                    ScrollViewer.ScrollChanged="OnEventScrollChanged"
+                    ScrollViewer.VerticalScrollBarVisibility="Visible"
+                    ScrollViewer.HorizontalScrollBarVisibility="Auto"
+                    VirtualizingPanel.IsVirtualizing="True"
+                    VirtualizingPanel.VirtualizationMode="Recycling">
+            <ListView.View>
+              <GridView>
+                <GridViewColumn Header="Time" Width="70" DisplayMemberBinding="{Binding Time}"/>
+                <GridViewColumn Header="Area" Width="100" DisplayMemberBinding="{Binding Category}"/>
+                <GridViewColumn Header="Detail" Width="440" DisplayMemberBinding="{Binding Message}"/>
+              </GridView>
+            </ListView.View>
+          </ListView>
+        </DockPanel>
+      </Grid>
+    </DockPanel>
+  </DockPanel>
+</Window>

src/Explorer.App/HostActivityMonitorWindow.xaml.cs

@@ -0,0 +1,139 @@
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Threading;
+using Explorer.Presentation.ViewModels;
+
+namespace Explorer.App;
+
+public partial class HostActivityMonitorWindow : Window
+{
+    private bool _stickToEnd = true;
+    private bool _scrollQueued;
+    private ScrollViewer? _eventScroll;
+
+    public HostActivityMonitorWindow(HostActivityMonitorViewModel vm)
+    {
+        InitializeComponent();
+        DataContext = vm;
+        ViewModel = vm;
+        ModelessWindowClose.EnableEscape(this);
+        StateChanged += (_, _) => SyncMaxRestoreButton();
+        vm.EventsReplaced += OnEventsReplaced;
+        Closed += (_, _) =>
+        {
+            vm.EventsReplaced -= OnEventsReplaced;
+            vm.Dispose();
+        };
+        Loaded += (_, _) =>
+        {
+            SyncMaxRestoreButton();
+            _eventScroll = FindScrollViewer(EventList);
+            vm.Start();
+        };
+    }
+
+    public HostActivityMonitorViewModel ViewModel { get; }
+
+    private void OnClose(object sender, RoutedEventArgs e) => Close();
+
+    private void OnMinimize(object sender, RoutedEventArgs e) => WindowState = WindowState.Minimized;
+
+    private void OnMaxRestore(object sender, RoutedEventArgs e) => ToggleMaximized();
+
+    private void OnTitleBarMouseDown(object sender, MouseButtonEventArgs e)
+    {
+        if (e.ChangedButton != MouseButton.Left)
+        {
+            return;
+        }
+
+        if (e.ClickCount == 2)
+        {
+            ToggleMaximized();
+            return;
+        }
+
+        DragMove();
+    }
+
+    private void ToggleMaximized()
+    {
+        WindowState = WindowState == WindowState.Maximized ? WindowState.Normal : WindowState.Maximized;
+        SyncMaxRestoreButton();
+    }
+
+    private void SyncMaxRestoreButton()
+        => MaxRestoreButton.Content = WindowState == WindowState.Maximized ? "❐" : "☐";
+
+    private void OnEventScrollChanged(object sender, ScrollChangedEventArgs e)
+    {
+        if (e.OriginalSource is not ScrollViewer viewer)
+        {
+            return;
+        }
+
+        _eventScroll = viewer;
+        if (e.ExtentHeightChange != 0)
+        {
+            return;
+        }
+
+        // Only treat intentional user scroll as leaving the live tail.
+        if (e.VerticalChange == 0)
+        {
+            return;
+        }
+
+        _stickToEnd = viewer.VerticalOffset >= viewer.ScrollableHeight - 8;
+    }
+
+    private void OnEventsReplaced(object? sender, EventArgs e)
+    {
+        if (!_stickToEnd || _scrollQueued)
+        {
+            return;
+        }
+
+        _scrollQueued = true;
+        Dispatcher.BeginInvoke(() =>
+        {
+            _scrollQueued = false;
+            if (!_stickToEnd)
+            {
+                return;
+            }
+
+            _eventScroll ??= FindScrollViewer(EventList);
+            if (_eventScroll is not null)
+            {
+                _eventScroll.ScrollToEnd();
+            }
+            else if (EventList.Items.Count > 0)
+            {
+                EventList.ScrollIntoView(EventList.Items[^1]);
+            }
+        }, DispatcherPriority.Background);
+    }
+
+    private static ScrollViewer? FindScrollViewer(DependencyObject root)
+    {
+        if (root is ScrollViewer scroll)
+        {
+            return scroll;
+        }
+
+        for (var i = 0; i < VisualTreeHelper.GetChildrenCount(root); i++)
+        {
+            var child = VisualTreeHelper.GetChild(root, i);
+            var found = FindScrollViewer(child);
+            if (found is not null)
+            {
+                return found;
+            }
+        }
+
+        return null;
+    }
+}

src/Explorer.App/MainWindow.xaml

@@ -183,6 +183,9 @@
           <MenuItem Header="_Operation profiles…" Click="OnOperationProfiles"/>
         </MenuItem>
         <MenuItem Header="_Development">
+          <MenuItem Header="_Host activity…" Click="OnHostActivity"/>
+          <MenuItem Header="_Database…" Click="OnDatabase"/>
+          <Separator/>
           <MenuItem Header="View _changes…" Click="OnGitChanges"
                     IsEnabled="{Binding ShowGitActions}"/>
           <MenuItem Header="_Commit…" Click="OnGitCommit"
@@ -986,66 +989,91 @@
       </Border>
 
       <Border Grid.Column="2" Background="#99000000" Visibility="{Binding Duplicates.IsOpen, Converter={StaticResource BoolVis}}">
-        <Border Background="{DynamicResource Panel}" BorderBrush="{DynamicResource Stroke}" BorderThickness="1" Margin="48" Padding="16">
-          <DockPanel>
-            <DockPanel DockPanel.Dock="Top" Margin="0,0,0,8">
+        <Border Background="{DynamicResource Panel}" BorderBrush="{DynamicResource Stroke}" BorderThickness="1"
+                Margin="48" Padding="16" VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
+          <Grid>
+            <Grid.RowDefinitions>
+              <RowDefinition Height="Auto"/>
+              <RowDefinition Height="Auto"/>
+              <RowDefinition Height="Auto"/>
+              <RowDefinition Height="Auto"/>
+              <RowDefinition Height="*"/>
+            </Grid.RowDefinitions>
+            <DockPanel Margin="0,0,0,8">
               <Button DockPanel.Dock="Right" Content="Close" Command="{Binding Duplicates.CloseCommand}"/>
               <TextBlock Text="Duplicates" FontSize="18" FontWeight="SemiBold" Foreground="{DynamicResource Fg}"/>
             </DockPanel>
-            <TextBlock DockPanel.Dock="Top" Text="{Binding Duplicates.Status}" Foreground="{DynamicResource Fg}" Margin="0,0,0,8" TextWrapping="Wrap"/>
-            <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Margin="0,0,0,8">
+            <TextBlock Grid.Row="1" Text="{Binding Duplicates.Status}" Foreground="{DynamicResource Fg}" Margin="0,0,0,8" TextWrapping="Wrap"/>
+            <StackPanel Grid.Row="2" Orientation="Horizontal" Margin="0,0,0,8">
               <CheckBox Content="Show intentional" IsChecked="{Binding Duplicates.ShowIntentional}" Margin="0,0,16,0"/>
               <CheckBox Content="Show hard links" IsChecked="{Binding Duplicates.ShowHardlinks}"/>
             </StackPanel>
-            <ProgressBar DockPanel.Dock="Top" Margin="0,0,0,8" IsIndeterminate="True"
+            <ProgressBar Grid.Row="3" Margin="0,0,0,8" IsIndeterminate="True"
                          Visibility="{Binding Duplicates.IsBusy, Converter={StaticResource BoolVis}}"/>
-            <ScrollViewer VerticalScrollBarVisibility="Auto">
-              <ItemsControl ItemsSource="{Binding Duplicates.Groups}">
-                <ItemsControl.ItemTemplate>
-                  <DataTemplate>
-                    <Border BorderBrush="{DynamicResource Stroke}" BorderThickness="0,0,0,1" Padding="0,10">
-                      <DockPanel>
-                        <DockPanel DockPanel.Dock="Top" Margin="0,0,0,6">
-                          <StackPanel DockPanel.Dock="Right" Orientation="Horizontal">
-                            <Button Content="Mark as intentional" Margin="0,0,6,0"
-                                    Command="{Binding DataContext.Duplicates.MarkIntentionalCommand, RelativeSource={RelativeSource AncestorType=Window}}"
-                                    CommandParameter="{Binding}"
-                                    Visibility="{Binding CanMarkIntentional, Converter={StaticResource BoolVis}}"/>
-                            <Button Content="Mark as accidental"
-                                    Command="{Binding DataContext.Duplicates.MarkAccidentalCommand, RelativeSource={RelativeSource AncestorType=Window}}"
-                                    CommandParameter="{Binding}"
-                                    Visibility="{Binding CanMarkAccidental, Converter={StaticResource BoolVis}}"/>
-                          </StackPanel>
-                          <TextBlock Foreground="{DynamicResource Fg}" FontWeight="SemiBold">
-                            <Run Text="{Binding ClassLabel, Mode=OneWay}"/>
-                            <Run Text=" · "/>
-                            <Run Text="{Binding SizeLabel, Mode=OneWay}"/>
-                            <Run Text=" · "/>
-                            <Run Text="{Binding Summary, Mode=OneWay}"/>
-                            <Run Text=" · "/>
-                            <Run Text="{Binding WastedLabel, Mode=OneWay}"/>
-                          </TextBlock>
-                        </DockPanel>
-                        <ItemsControl ItemsSource="{Binding Files}">
-                          <ItemsControl.ItemTemplate>
-                            <DataTemplate>
-                              <DockPanel Margin="0,2">
-                                <Button DockPanel.Dock="Right" Content="Show in Explorer" Margin="8,0,0,0"
-                                        Command="{Binding DataContext.Duplicates.RevealCommand, RelativeSource={RelativeSource AncestorType=Window}}"
-                                        CommandParameter="{Binding}"/>
-                                <TextBlock Text="{Binding LocationLabel}" Foreground="{DynamicResource FgMuted}"
-                                           TextTrimming="CharacterEllipsis" VerticalAlignment="Center"/>
-                              </DockPanel>
-                            </DataTemplate>
-                          </ItemsControl.ItemTemplate>
-                        </ItemsControl>
+            <ListBox Grid.Row="4"
+                     ItemsSource="{Binding Duplicates.Groups}"
+                     Background="Transparent"
+                     BorderThickness="0"
+                     Padding="0"
+                     HorizontalContentAlignment="Stretch"
+                     ScrollViewer.CanContentScroll="True"
+                     ScrollViewer.HorizontalScrollBarVisibility="Disabled"
+                     ScrollViewer.VerticalScrollBarVisibility="Visible"
+                     VirtualizingPanel.IsVirtualizing="True"
+                     VirtualizingPanel.VirtualizationMode="Recycling"
+                     VirtualizingPanel.ScrollUnit="Pixel">
+              <ListBox.ItemContainerStyle>
+                <Style TargetType="ListBoxItem">
+                  <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
+                  <Setter Property="Padding" Value="0"/>
+                  <Setter Property="Margin" Value="0"/>
+                  <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
+                  <Setter Property="Template">
+                    <Setter.Value>
+                      <ControlTemplate TargetType="ListBoxItem">
+                        <ContentPresenter HorizontalAlignment="Stretch"/>
+                      </ControlTemplate>
+                    </Setter.Value>
+                  </Setter>
+                </Style>
+              </ListBox.ItemContainerStyle>
+              <ListBox.ItemTemplate>
+                <DataTemplate>
+                  <Border BorderBrush="{DynamicResource Stroke}" BorderThickness="0,0,0,1" Padding="0,10">
+                    <DockPanel>
+                      <DockPanel DockPanel.Dock="Top" Margin="0,0,0,6">
+                        <StackPanel DockPanel.Dock="Right" Orientation="Horizontal">
+                          <Button Content="Mark as intentional" Margin="0,0,6,0"
+                                  Command="{Binding DataContext.Duplicates.MarkIntentionalCommand, RelativeSource={RelativeSource AncestorType=Window}}"
+                                  CommandParameter="{Binding}"
+                                  Visibility="{Binding CanMarkIntentional, Converter={StaticResource BoolVis}}"/>
+                          <Button Content="Mark as accidental"
+                                  Command="{Binding DataContext.Duplicates.MarkAccidentalCommand, RelativeSource={RelativeSource AncestorType=Window}}"
+                                  CommandParameter="{Binding}"
+                                  Visibility="{Binding CanMarkAccidental, Converter={StaticResource BoolVis}}"/>
+                        </StackPanel>
+                        <TextBlock Text="{Binding Header, Mode=OneWay}" Foreground="{DynamicResource Fg}" FontWeight="SemiBold"
+                                   TextTrimming="CharacterEllipsis"/>
                       </DockPanel>
-                    </Border>
-                  </DataTemplate>
-                </ItemsControl.ItemTemplate>
-              </ItemsControl>
-            </ScrollViewer>
-          </DockPanel>
+                      <ItemsControl ItemsSource="{Binding Files}">
+                        <ItemsControl.ItemTemplate>
+                          <DataTemplate>
+                            <DockPanel Margin="0,2">
+                              <Button DockPanel.Dock="Right" Content="Show in Explorer" Margin="8,0,0,0"
+                                      Command="{Binding DataContext.Duplicates.RevealCommand, RelativeSource={RelativeSource AncestorType=Window}}"
+                                      CommandParameter="{Binding}"/>
+                              <TextBlock Text="{Binding LocationLabel}" Foreground="{DynamicResource FgMuted}"
+                                         TextTrimming="CharacterEllipsis" VerticalAlignment="Center"/>
+                            </DockPanel>
+                          </DataTemplate>
+                        </ItemsControl.ItemTemplate>
+                      </ItemsControl>
+                    </DockPanel>
+                  </Border>
+                </DataTemplate>
+              </ListBox.ItemTemplate>
+            </ListBox>
+          </Grid>
         </Border>
       </Border>
     </Grid>

src/Explorer.App/MainWindow.xaml.cs

@@ -18,11 +18,14 @@ public partial class MainWindow : Window
 {
     private DocumentationWindow? _docs;
     private GitChangesWindow? _gitChanges;
+    private HostActivityMonitorWindow? _hostActivity;
+    private DatabaseWindow? _database;
     private Point _dragStart;
     private bool _dragPending;
     private MouseButton _dragButton;
     private FolderItemViewModel? _dragItem;
     private ListView? _dragList;
+    private bool _draggingFromHere;
     private FolderItemViewModel[] _dragSelection = [];
     private bool _dragFromMultiSelect;
     private bool _syncingSelection;
@@ -661,7 +664,7 @@ public partial class MainWindow : Window
         }
 
         _suppressItemContextMenu = false;
-        _dragStart = e.GetPosition(null);
+        _dragStart = e.GetPosition(this);
         _dragPending = true;
         _dragButton = e.ChangedButton;
         _dragList = sender as ListView;
@@ -739,11 +742,12 @@ public partial class MainWindow : Window
                            && dest is not null
                            && NavigationTreeViewModel.PathsEqual(hover.FullPath, dest)
                            && !DragDropPolicy.IsInvalidTarget(files, dest)
+                           && !IsRedundantLeftDrop(files, dest)
             ? hover
             : null;
         SetListDropTarget(folderTarget);
         SetTreeDropTarget(null);
-        if (dest is null || DragDropPolicy.IsInvalidTarget(files, dest))
+        if (dest is null || DragDropPolicy.IsInvalidTarget(files, dest) || IsRedundantLeftDrop(files, dest))
         {
             e.Effects = DragDropEffects.None;
             e.Handled = true;
@@ -786,6 +790,11 @@ public partial class MainWindow : Window
             return;
         }
 
+        if (IsRedundantLeftDrop(files, dest))
+        {
+            return;
+        }
+
         await ApplyDropAsync(files, dest, ResolveDropAction(e, files, dest)).ConfigureAwait(true);
     }
 
@@ -863,9 +872,8 @@ public partial class MainWindow : Window
             return;
         }
 
-        var pos = e.GetPosition(null);
-        if (Math.Abs(pos.X - _dragStart.X) < SystemParameters.MinimumHorizontalDragDistance
-            && Math.Abs(pos.Y - _dragStart.Y) < SystemParameters.MinimumVerticalDragDistance)
+        var pos = e.GetPosition(this);
+        if (!DragMovedEnough(pos, DragDropPolicy.DragStartDistance))
         {
             return;
         }
@@ -887,10 +895,18 @@ public partial class MainWindow : Window
         _sourceRightDrag = _dragButton == MouseButton.Right;
         _suppressItemContextMenu = _sourceRightDrag;
         var data = new DataObject(DataFormats.FileDrop, paths.ToArray());
-        DragDrop.DoDragDrop(this, data, DragDropEffects.Copy | DragDropEffects.Move | DragDropEffects.Link);
-        _sourceRightDrag = false;
-        _incomingRightDrag = false;
-        ClearDropTargets();
+        _draggingFromHere = true;
+        try
+        {
+            DragDrop.DoDragDrop(this, data, DragDropEffects.Copy | DragDropEffects.Move | DragDropEffects.Link);
+        }
+        finally
+        {
+            _draggingFromHere = false;
+            _sourceRightDrag = false;
+            _incomingRightDrag = false;
+            ClearDropTargets();
+        }
     }
 
     protected override void OnQueryContinueDrag(QueryContinueDragEventArgs e)
@@ -1017,16 +1033,58 @@ public partial class MainWindow : Window
     private string? ResolveDropDirectory(ListView list, DragEventArgs e)
     {
         var item = HitTestFolderItem(list, e.GetPosition(list));
-        if (item is { IsDirectory: true })
+        if (!_draggingFromHere)
+        {
+            if (item is { IsDirectory: true })
+            {
+                return item.FullPath;
+            }
+
+            return CurrentListDirectory(list);
+        }
+
+        var pos = e.GetPosition(this);
+        if (item is { IsDirectory: true }
+            && DragMovedEnough(pos, FolderDropDistance(list)))
         {
             return item.FullPath;
         }
 
+        if (!ReferenceEquals(list, _dragList)
+            && !DragMovedEnough(pos, DragDropPolicy.DropCrossViewDistance))
+        {
+            return null;
+        }
+
+        return CurrentListDirectory(list);
+    }
+
+    private string? CurrentListDirectory(ListView list)
+    {
         var tab = Vm.ActiveTab;
         var path = list.ItemsSource == tab.Right.Items ? tab.Right.CurrentPath : tab.Left.CurrentPath;
         return LocationRoots.IsVirtual(path) ? null : path;
     }
 
+    private double FolderDropDistance(ListView list)
+        => ReferenceEquals(list, _dragList)
+            ? DragDropPolicy.DropIntoItemDistance
+            : DragDropPolicy.DropCrossViewDistance;
+
+    private bool DragMovedEnough(Point current, double preferred)
+        => DragDropPolicy.ExceedsDistance(
+            current.X - _dragStart.X,
+            current.Y - _dragStart.Y,
+            Math.Max(preferred, SystemDragMinimum));
+
+    private static double SystemDragMinimum
+        => Math.Max(SystemParameters.MinimumHorizontalDragDistance, SystemParameters.MinimumVerticalDragDistance);
+
+    private bool IsRedundantLeftDrop(IReadOnlyList<string> files, string dest)
+        => !_sourceRightDrag
+           && !_incomingRightDrag
+           && DragDropPolicy.AllAlreadyInDirectory(files, dest);
+
     private static FolderItemViewModel? HitTestFolderItem(DependencyObject? origin, Point point)
     {
         if (origin is not Visual visual)
@@ -1178,6 +1236,11 @@ public partial class MainWindow : Window
             return;
         }
 
+        if (IsRedundantLeftDrop(files, dest))
+        {
+            return;
+        }
+
         await ApplyDropAsync(files, dest, ResolveDropAction(e, files, dest)).ConfigureAwait(true);
     }
 
@@ -1848,6 +1911,48 @@ public partial class MainWindow : Window
     private void OnAbout(object sender, RoutedEventArgs e)
         => new AboutWindow { Owner = this }.ShowDialog();
 
+    private void OnHostActivity(object sender, RoutedEventArgs e)
+    {
+        if (_hostActivity is { IsVisible: true })
+        {
+            _hostActivity.Activate();
+            return;
+        }
+
+        var vm = Vm.CreateHostActivityMonitorViewModel();
+        if (vm is null)
+        {
+            MessageBox.Show(this, "Host activity is unavailable until the background host is connected.",
+                "Explorer Workbench", MessageBoxButton.OK, MessageBoxImage.Information);
+            return;
+        }
+
+        _hostActivity = new HostActivityMonitorWindow(vm) { Owner = this };
+        _hostActivity.Closed += (_, _) => _hostActivity = null;
+        _hostActivity.Show();
+    }
+
+    private void OnDatabase(object sender, RoutedEventArgs e)
+    {
+        if (_database is { IsVisible: true })
+        {
+            _database.Activate();
+            return;
+        }
+
+        var vm = Vm.CreateDatabaseViewerViewModel();
+        if (vm is null)
+        {
+            MessageBox.Show(this, "Database tools are unavailable.",
+                "Explorer Workbench", MessageBoxButton.OK, MessageBoxImage.Information);
+            return;
+        }
+
+        _database = new DatabaseWindow(vm) { Owner = this };
+        _database.Closed += (_, _) => _database = null;
+        _database.Show();
+    }
+
     private async void OnGitChanges(object sender, RoutedEventArgs e)
     {
         if (_gitChanges is { IsVisible: true })

src/Explorer.App/ModelessWindowClose.cs

@@ -0,0 +1,23 @@
+using System.Windows;
+using System.Windows.Input;
+
+namespace Explorer.App;
+
+/// <summary>
+/// Close helpers for windows opened with <see cref="Window.Show"/>.
+/// <see cref="Button.IsCancel"/> sets <see cref="Window.DialogResult"/>, which throws on modeless windows.
+/// </summary>
+internal static class ModelessWindowClose
+{
+    public static void EnableEscape(Window window)
+        => window.PreviewKeyDown += (_, e) =>
+        {
+            if (e.Key != Key.Escape)
+            {
+                return;
+            }
+
+            window.Close();
+            e.Handled = true;
+        };
+}