Query history improvments (#336)

* Fix sort issues on the QueryHistory

* What changed
1. QueryStoreGridControl.Selection.cs — ViewHistory_Click now walks up the visual tree to find the parent QuerySessionControl and calls AddHistorySubTab(), placing the history as a sub-tab alongside "Query Store — DB" and "QS Overview" (instead of at the top-level MainTabControl).
2. QuerySessionControl.QueryStore.cs — Added two new methods:
• AddHistorySubTab() — creates a closeable sub-tab with the history control, including long-press (~500ms) to detach into a free-floating window
• DetachHistorySubTabToWindow() — pops the history content into a standalone non-modal window (movable to another screen). When that window is minimized or closed, the content automatically re-docks back as a sub-tab
3. MainWindow.Tabs.cs — Removed the now-unused AddHistoryTab() method since history tabs no longer live at the top level

User flow
• View History → opens as a sub-tab next to Query Store / QS Overview
• Long-press the history sub-tab → detaches into a free window (can move to another screen)
• Minimize or close the free window → content returns to the sub-tab

* What was added
1. QueryStoreService.FetchPlanByHashAsync() — New method that fetches a plan XML from sys.query_store_plan by query_plan_hash. The oldest parameter controls whether it returns the first (smallest plan_id) or last (largest plan_id) plan.
2. Context menu on QueryStoreHistoryControl — Right-clicking on the DataGrid or chart shows:
• "Load the First Plan" — fetches the oldest plan for the selected plan hash
• "Load the Last Plan" — fetches the most recent plan for the selected plan hash
The selected plan hash is determined from either the grid selection or chart selection.
3. PlanLoadRequested event — Raised when the user picks a plan from the context menu. The parent QuerySessionControl subscribes to this event and opens the plan XML as a new sub-tab (using the existing AddPlanTab mechanism).

User flow
• Select a row in the history grid (or a dot on the chart)
• Right-click → "Load the First Plan" or "Load the Last Plan"
• The plan opens as a new sub-tab (e.g., "QS 42 / 17")

* Code review :

Bugs Fixed
1. Shared ContextMenu — BuildContextMenu() now creates separate ContextMenu instances for DataGrid and Chart via CreatePlanContextMenu()
2. Silent catch — LoadPlanFromSelection now shows errors in StatusText with catch (Exception ex)
3. Wrong type check — Close_Click now checks is not PlanViewer.App.MainWindow instead of IClassicDesktopStyleApplicationLifetime
4. Event handler leak — AddHistorySubTab now unsubscribes before subscribing: -= OnHistoryPlanLoadRequested before +=
Improvements
5. Loading feedback — Shows "Loading plan…" / "Plan not found" / error in StatusText
6. Disable menu when no selection — Opening handler disables items when GetSelectedPlanHash() is null
7. IndexOf — Added clarifying comment (list is <500 items, no better API available)
8. ScrollIntoView — Moved after ItemsSource reset so the target row exists
9. Long-press duplication — Extracted TabHeaderLongPressBehavior helper, used in both MainWindow.Tabs.cs and QuerySessionControl.QueryStore.cs
10. HistoryPlanLoadEventArgs — Moved to its own file
Nits
11. Removed unnecessary ?. on non-nullable orderBy parameter
12. Changed bare catch to catch (Exception) in tooltip handler
13. Changed bare catch to catch (Exception ex) in LoadPlanFromSelection

* When the MainWindow closes, it now iterates all open windows via IClassicDesktopStyleApplicationLifetime.Windows and closes any that aren't the MainWindow itself. This ensures all detached free-floating windows (from tab detach, history detach, advice windows, etc.) are closed when the app's main window is closed.

* Must-fix fixed

* use pin/unpin button to fix ux-must-fix

* fix error truncation to 80 chars : truncation removed

* fix most remaining nice to have

* add spinner and cancel for history fetches

Author: rferraton

src/PlanViewer.App/Controls/HistoryPlanLoadEventArgs.cs

@@ -0,0 +1,17 @@
+using System;
+using PlanViewer.Core.Models;
+
+namespace PlanViewer.App.Controls;
+
+/// <summary>
+/// Event args for when a plan is loaded from the history context menu.
+/// </summary>
+public class HistoryPlanLoadEventArgs : EventArgs
+{
+	public QueryStorePlan Plan { get; }
+
+	public HistoryPlanLoadEventArgs(QueryStorePlan plan)
+	{
+		Plan = plan;
+	}
+}

src/PlanViewer.App/Controls/QuerySessionControl.QueryStore.cs

@@ -19,6 +19,7 @@
 using AvaloniaEdit.TextMate;
 using Microsoft.Data.SqlClient;
 using PlanViewer.App.Dialogs;
+using PlanViewer.App.Helpers;
 using PlanViewer.App.Services;
 using PlanViewer.Core.Interfaces;
 using PlanViewer.Core.Models;
@@ -38,31 +39,15 @@ private bool HasQueryStoreTab()
 
     public void TriggerQueryStore() => QueryStore_Click(null, new RoutedEventArgs());
 
-    private async void QueryStoreOverview_Click(object? sender, RoutedEventArgs e)
+    /// <summary>
+    /// Creates a sub-tab with a standard header (label + optional extra buttons + close button).
+    /// Returns the TabItem. The close button removes the tab from SubTabControl.
+    /// </summary>
+    private TabItem CreateSubTab(string label, Control content, Action<TabItem>? onClose = null, params Button[] extraButtons)
     {
-        if (_serverConnection == null || _connectionString == null)
-        {
-            await ShowConnectionDialogAsync();
-            if (_serverConnection == null || _connectionString == null)
-                return;
-        }
-
-        SetStatus("Loading Query Store Overview...");
-
-        var supportsWaitStats = _serverMetadata?.SupportsQueryStoreWaitStats ?? false;
-        var overview = new QueryStoreOverviewControl(_serverConnection, _credentialService,
-            supportsWaitStats: supportsWaitStats);
-        overview.DrillDownRequested += async (_, args) =>
-        {
-            // Open a single-database Query Store tab directly (no connection dialog)
-            _selectedDatabase = args.Database;
-            _connectionString = _serverConnection!.GetConnectionString(_credentialService, args.Database);
-            await OpenQueryStoreForDatabaseAsync(args.Database, args.StartUtc, args.EndUtc);
-        };
-
         var headerText = new TextBlock
         {
-            Text = "QS Overview",
+            Text = label,
             VerticalAlignment = Avalonia.Layout.VerticalAlignment.Center,
             FontSize = 12
         };
@@ -73,7 +58,7 @@ private async void QueryStoreOverview_Click(object? sender, RoutedEventArgs e)
             MinWidth = 22, MinHeight = 22, Width = 22, Height = 22,
             Padding = new Avalonia.Thickness(0),
             FontSize = 11,
-            Margin = new Avalonia.Thickness(6, 0, 0, 0),
+            Margin = new Avalonia.Thickness(2, 0, 0, 0),
             Background = Brushes.Transparent,
             BorderThickness = new Avalonia.Thickness(0),
             Foreground = new SolidColorBrush(Color.FromRgb(0xE4, 0xE6, 0xEB)),
@@ -85,17 +70,58 @@ private async void QueryStoreOverview_Click(object? sender, RoutedEventArgs e)
         var header = new StackPanel
         {
             Orientation = Avalonia.Layout.Orientation.Horizontal,
-            Children = { headerText, closeBtn }
+            Background = Brushes.Transparent
         };
+        header.Children.Add(headerText);
+        foreach (var btn in extraButtons)
+            header.Children.Add(btn);
+        header.Children.Add(closeBtn);
 
-        var tab = new TabItem { Header = header, Content = overview };
+        var tab = new TabItem { Header = header, Content = content };
         closeBtn.Tag = tab;
         closeBtn.Click += (s, _) =>
         {
             if (s is Button btn && btn.Tag is TabItem t)
+            {
+                onClose?.Invoke(t);
                 SubTabControl.Items.Remove(t);
+            }
+        };
+
+        return tab;
+    }
+
+    /// <summary>Gets the header TextBlock from a sub-tab created via CreateSubTab.</summary>
+    private static TextBlock? GetSubTabHeaderText(TabItem tab)
+    {
+        if (tab.Header is StackPanel sp && sp.Children.Count > 0 && sp.Children[0] is TextBlock tb)
+            return tb;
+        return null;
+    }
+
+    private async void QueryStoreOverview_Click(object? sender, RoutedEventArgs e)
+    {
+        if (_serverConnection == null || _connectionString == null)
+        {
+            await ShowConnectionDialogAsync();
+            if (_serverConnection == null || _connectionString == null)
+                return;
+        }
+
+        SetStatus("Loading Query Store Overview...");
+
+        var supportsWaitStats = _serverMetadata?.SupportsQueryStoreWaitStats ?? false;
+        var overview = new QueryStoreOverviewControl(_serverConnection, _credentialService,
+            supportsWaitStats: supportsWaitStats);
+        overview.DrillDownRequested += async (_, args) =>
+        {
+            // Open a single-database Query Store tab directly (no connection dialog)
+            _selectedDatabase = args.Database;
+            _connectionString = _serverConnection!.GetConnectionString(_credentialService, args.Database);
+            await OpenQueryStoreForDatabaseAsync(args.Database, args.StartUtc, args.EndUtc);
         };
 
+        var tab = CreateSubTab("QS Overview", overview);
         SubTabControl.Items.Add(tab);
         SubTabControl.SelectedItem = tab;
 
@@ -106,7 +132,7 @@ private async void QueryStoreOverview_Click(object? sender, RoutedEventArgs e)
         }
         catch (Exception ex)
         {
-            SetStatus(ex.Message.Length > 80 ? ex.Message[..80] + "..." : ex.Message, autoClear: false);
+            SetStatus(ex.Message, autoClear: false);
         }
     }
 
@@ -127,7 +153,7 @@ private async Task OpenQueryStoreForDatabaseAsync(string database, DateTime? ini
         }
         catch (Exception ex)
         {
-            SetStatus(ex.Message.Length > 80 ? ex.Message[..80] + "..." : ex.Message, autoClear: false);
+            SetStatus(ex.Message, autoClear: false);
             return;
         }
 
@@ -152,41 +178,11 @@ private async Task OpenQueryStoreForDatabaseAsync(string database, DateTime? ini
             grid.SetInitialTimeRange(initialStartUtc.Value, initialEndUtc.Value);
         grid.PlansSelected += OnQueryStorePlansSelected;
 
-        var headerText = new TextBlock
-        {
-            Text = $"Query Store — {database}",
-            VerticalAlignment = Avalonia.Layout.VerticalAlignment.Center,
-            FontSize = 12
-        };
-        grid.DatabaseChanged += (_, db) => headerText.Text = $"Query Store — {db}";
-
-        var closeBtn = new Button
-        {
-            Content = "\u2715",
-            MinWidth = 22, MinHeight = 22, Width = 22, Height = 22,
-            Padding = new Avalonia.Thickness(0),
-            FontSize = 11,
-            Margin = new Avalonia.Thickness(6, 0, 0, 0),
-            Background = Brushes.Transparent,
-            BorderThickness = new Avalonia.Thickness(0),
-            Foreground = new SolidColorBrush(Color.FromRgb(0xE4, 0xE6, 0xEB)),
-            VerticalAlignment = Avalonia.Layout.VerticalAlignment.Center,
-            HorizontalContentAlignment = HorizontalAlignment.Center,
-            VerticalContentAlignment = VerticalAlignment.Center
-        };
-
-        var header = new StackPanel
-        {
-            Orientation = Avalonia.Layout.Orientation.Horizontal,
-            Children = { headerText, closeBtn }
-        };
-
-        var tab = new TabItem { Header = header, Content = grid };
-        closeBtn.Tag = tab;
-        closeBtn.Click += (s, _) =>
+        var tab = CreateSubTab($"Query Store — {database}", grid);
+        grid.DatabaseChanged += (_, db) =>
         {
-            if (s is Button btn && btn.Tag is TabItem t)
-                SubTabControl.Items.Remove(t);
+            if (GetSubTabHeaderText(tab) is TextBlock tb)
+                tb.Text = $"Query Store — {db}";
         };
 
         SubTabControl.Items.Add(tab);
@@ -244,62 +240,112 @@ private async void QueryStore_Click(object? sender, RoutedEventArgs e)
             _selectedDatabase!, databases, supportsWaitStats);
         grid.PlansSelected += OnQueryStorePlansSelected;
 
-        var headerText = new TextBlock
-        {
-            Text = $"Query Store — {_selectedDatabase}",
-            VerticalAlignment = Avalonia.Layout.VerticalAlignment.Center,
-            FontSize = 12
-        };
-
+        var tab = CreateSubTab($"Query Store — {_selectedDatabase}", grid);
         // Update tab header when database is changed via the grid's picker
         grid.DatabaseChanged += (_, db) =>
         {
-            headerText.Text = $"Query Store — {db}";
+            if (GetSubTabHeaderText(tab) is TextBlock tb)
+                tb.Text = $"Query Store — {db}";
         };
 
-        var closeBtn = new Button
+        SubTabControl.Items.Add(tab);
+        SubTabControl.SelectedItem = tab;
+    }
+
+    private void OnQueryStorePlansSelected(object? sender, List<QueryStorePlan> plans)
+    {
+        foreach (var qsPlan in plans)
         {
-            Content = "\u2715",
+            var tabLabel = $"QS {qsPlan.QueryId} / {qsPlan.PlanId}";
+            AddPlanTab(qsPlan.PlanXml, qsPlan.QueryText, estimated: true, labelOverride: tabLabel);
+        }
+
+        SetStatus($"{plans.Count} Query Store plans loaded");
+        HumanAdviceButton.IsEnabled = true;
+        RobotAdviceButton.IsEnabled = true;
+    }
+
+    /// <summary>
+    /// Adds a Query Store History control as a sub-tab in this session.
+    /// Supports long-press to detach into a free-floating window.
+    /// </summary>
+    public void AddHistorySubTab(string label, QueryStoreHistoryControl control)
+    {
+        // Wire up plan load from context menu (unsubscribe first to prevent leaks on re-dock)
+        control.PlanLoadRequested -= OnHistoryPlanLoadRequested;
+        control.PlanLoadRequested += OnHistoryPlanLoadRequested;
+
+        var detachBtn = new Button
+        {
+            Content = "↗",
             MinWidth = 22, MinHeight = 22, Width = 22, Height = 22,
             Padding = new Avalonia.Thickness(0),
             FontSize = 11,
-            Margin = new Avalonia.Thickness(6, 0, 0, 0),
+            Margin = new Avalonia.Thickness(4, 0, 0, 0),
             Background = Brushes.Transparent,
             BorderThickness = new Avalonia.Thickness(0),
-            Foreground = new SolidColorBrush(Color.FromRgb(0xE4, 0xE6, 0xEB)),
+            Foreground = new SolidColorBrush(Color.FromRgb(0xA0, 0xA0, 0xA0)),
             VerticalAlignment = Avalonia.Layout.VerticalAlignment.Center,
             HorizontalContentAlignment = HorizontalAlignment.Center,
             VerticalContentAlignment = VerticalAlignment.Center
         };
+        Avalonia.Controls.ToolTip.SetTip(detachBtn, "Detach to Window");
 
-        var header = new StackPanel
-        {
-            Orientation = Avalonia.Layout.Orientation.Horizontal,
-            Children = { headerText, closeBtn }
-        };
+        var tab = CreateSubTab(label, control,
+            onClose: t => { if (t.Content is QueryStoreHistoryControl hc) hc.CancelFetch(); },
+            detachBtn);
 
-        var tab = new TabItem { Header = header, Content = grid };
-        closeBtn.Tag = tab;
-        closeBtn.Click += (s, _) =>
+        detachBtn.Tag = tab;
+        detachBtn.Click += (s, _) =>
         {
             if (s is Button btn && btn.Tag is TabItem t)
-                SubTabControl.Items.Remove(t);
+                DetachHistorySubTabToWindow(t);
         };
 
         SubTabControl.Items.Add(tab);
         SubTabControl.SelectedItem = tab;
     }
 
-    private void OnQueryStorePlansSelected(object? sender, List<QueryStorePlan> plans)
+    private void OnHistoryPlanLoadRequested(object? sender, HistoryPlanLoadEventArgs e)
     {
-        foreach (var qsPlan in plans)
-        {
-            var tabLabel = $"QS {qsPlan.QueryId} / {qsPlan.PlanId}";
-            AddPlanTab(qsPlan.PlanXml, qsPlan.QueryText, estimated: true, labelOverride: tabLabel);
-        }
+        var plan = e.Plan;
+        var tabLabel = $"QS {plan.QueryId} / {plan.PlanId}";
+        AddPlanTab(plan.PlanXml, plan.QueryText, estimated: true, labelOverride: tabLabel);
+    }
 
-        SetStatus($"{plans.Count} Query Store plans loaded");
-        HumanAdviceButton.IsEnabled = true;
-        RobotAdviceButton.IsEnabled = true;
+    /// <summary>
+    /// Detaches a history sub-tab into a standalone free-floating window.
+    /// Close = destroy. A Re-dock button allows explicit return to sub-tabs.
+    /// </summary>
+    private void DetachHistorySubTabToWindow(TabItem tab)
+    {
+        var content = tab.Content as QueryStoreHistoryControl;
+        if (content == null) return;
+
+        var tabLabel = GetSubTabHeaderText(tab)?.Text ?? "History";
+
+        // Remove from sub-tabs
+        SubTabControl.Items.Remove(tab);
+        tab.Content = null;
+
+        var mainWindow = Avalonia.Controls.TopLevel.GetTopLevel(this) as Window;
+
+        content.ShowCloseButton(false);
+
+        DetachedWindowHelper.ShowDetached(
+            content,
+            title: tabLabel,
+            icon: mainWindow?.Icon,
+            backgroundBrush: (Avalonia.Media.IBrush?)this.FindResource("BackgroundBrush"),
+            onRedock: c =>
+            {
+                if (mainWindow is not MainWindow mw || !mw.IsShuttingDown)
+                    AddHistorySubTab(tabLabel, (QueryStoreHistoryControl)c);
+            },
+            onClosing: c =>
+            {
+                if (c is QueryStoreHistoryControl hc)
+                    hc.CancelFetch();
+            });
     }
 }

src/PlanViewer.App/Controls/QueryStoreGridControl.Selection.cs

@@ -87,14 +87,14 @@ private static List<QueryStorePlan> CollectLeafPlans(QueryStoreRow row)
         return plans;
     }
 
-    private async void ViewHistory_Click(object? sender, RoutedEventArgs e)
+    private void ViewHistory_Click(object? sender, RoutedEventArgs e)
     {
         if (ResultsGrid.SelectedItem is not QueryStoreRow row) return;
         if (string.IsNullOrEmpty(row.QueryHash)) return;
 
         var metricTag = QueryStoreHistoryWindow.MapOrderByToMetricTag(_lastFetchedOrderBy);
 
-        var window = new QueryStoreHistoryWindow(
+        var control = new QueryStoreHistoryControl(
             _connectionString,
             row.QueryHash,
             row.FullQueryText,
@@ -104,11 +104,28 @@ private async void ViewHistory_Click(object? sender, RoutedEventArgs e)
             slicerEndUtc: _slicerEndUtc,
             slicerDaysBack: _slicerDaysBack);
 
-        var topLevel = Avalonia.Controls.TopLevel.GetTopLevel(this);
-        if (topLevel is Window parentWindow)
-            await window.ShowDialog(parentWindow);
+        var shortHash = row.QueryHash.Length > 8 ? row.QueryHash[..8] + "…" : row.QueryHash;
+
+        // Walk up the visual tree to find the parent QuerySessionControl
+        var session = this.FindAncestorOfType<QuerySessionControl>();
+        if (session != null)
+        {
+            session.AddHistorySubTab($"History: {shortHash}", control);
+        }
         else
+        {
+            // Fallback: open as standalone window
+            var window = new QueryStoreHistoryWindow(
+                _connectionString,
+                row.QueryHash,
+                row.FullQueryText,
+                _database,
+                initialMetricTag: metricTag,
+                slicerStartUtc: _slicerStartUtc,
+                slicerEndUtc: _slicerEndUtc,
+                slicerDaysBack: _slicerDaysBack);
             window.Show();
+        }
     }
 
     private void ContextMenu_Opening(object? sender, System.ComponentModel.CancelEventArgs e)