Fix Wait Stats selection with poison waits + top 10 (#12)

Dashboard/Controls/ResourceMetricsContent.xaml

@@ -110,8 +110,9 @@
                             <Button Content="Refresh" Click="WaitStatsDetail_Refresh_Click" Margin="10,0,0,0" Padding="8,2" Style="{StaticResource SuccessButton}" FontSize="11"/>
                         </StackPanel>
                         <StackPanel Grid.Row="1" Orientation="Horizontal" Margin="5,2">
-                            <Button Content="Select All" Click="WaitTypes_SelectAll_Click" Padding="6,2" FontSize="10" Margin="0,0,5,0"/>
+                            <Button Content="Top Waits" Click="WaitTypes_SelectAll_Click" Padding="6,2" FontSize="10" Margin="0,0,5,0"/>
                             <Button Content="Clear All" Click="WaitTypes_ClearAll_Click" Padding="6,2" FontSize="10"/>
+                            <TextBlock x:Name="WaitTypeCountText" Text="0 / 20 selected" FontSize="10" Foreground="{DynamicResource ForegroundMutedBrush}" VerticalAlignment="Center" Margin="8,0,0,0"/>
                         </StackPanel>
                         <TextBox Grid.Row="2" x:Name="WaitTypeSearchBox" Margin="5,2" Height="24" FontSize="11"
                                  TextChanged="WaitTypeSearch_TextChanged"

Dashboard/Controls/ResourceMetricsContent.xaml.cs

@@ -1862,6 +1862,17 @@ private void RefreshWaitTypeListOrder()
                 .ToList();
             _waitTypeItems = sorted;
             ApplyWaitTypeSearchFilter();
+            UpdateWaitTypeCount();
+        }
+
+        private void UpdateWaitTypeCount()
+        {
+            if (_waitTypeItems == null || WaitTypeCountText == null) return;
+            int count = _waitTypeItems.Count(x => x.IsSelected);
+            WaitTypeCountText.Text = $"{count} / 20 selected";
+            WaitTypeCountText.Foreground = count >= 20
+                ? new System.Windows.Media.SolidColorBrush((System.Windows.Media.Color)System.Windows.Media.ColorConverter.ConvertFromString("#E57373")!)
+                : (System.Windows.Media.Brush)FindResource("ForegroundMutedBrush");
         }
 
         private void WaitTypeSearch_TextChanged(object sender, TextChangedEventArgs e)
@@ -1897,19 +1908,10 @@ private async void WaitTypes_SelectAll_Click(object sender, RoutedEventArgs e)
         {
             if (_waitTypeItems == null) return;
             _isUpdatingWaitTypeSelection = true;
-            // Only select first 12 (color limit)
-            int count = 0;
+            var topWaits = TabHelpers.GetDefaultWaitTypes(_waitTypeItems.Select(x => x.WaitType).ToList());
             foreach (var item in _waitTypeItems)
             {
-                if (count < 12)
-                {
-                    item.IsSelected = true;
-                    count++;
-                }
-                else
-                {
-                    item.IsSelected = false;
-                }
+                item.IsSelected = topWaits.Contains(item.WaitType);
             }
             _isUpdatingWaitTypeSelection = false;
             RefreshWaitTypeListOrder();
@@ -1925,6 +1927,7 @@ private async void WaitTypes_ClearAll_Click(object sender, RoutedEventArgs e)
                 item.IsSelected = false;
             }
             _isUpdatingWaitTypeSelection = false;
+            UpdateWaitTypeCount();
             await UpdateWaitStatsDetailChartAsync();
         }
 
@@ -1961,22 +1964,14 @@ private async Task RefreshWaitStatsDetailTabAsync()
                     })
                     .ToList();
 
-                // If nothing was previously selected, default select some common wait types
+                // If nothing was previously selected, apply poison waits + usual suspects + top 10
                 if (!waitTypes.Any(w => w.IsSelected))
                 {
-                    var defaultWaitTypes = new[] { "CXPACKET", "SOS_SCHEDULER_YIELD", "PAGEIOLATCH_SH", "LCK_M_X", "ASYNC_NETWORK_IO", "WRITELOG" };
-                    foreach (var item in waitTypes.Where(w => defaultWaitTypes.Contains(w.WaitType)))
+                    var topWaits = TabHelpers.GetDefaultWaitTypes(waitTypes.Select(w => w.WaitType).ToList());
+                    foreach (var item in waitTypes.Where(w => topWaits.Contains(w.WaitType)))
                     {
                         item.IsSelected = true;
                     }
-                    // If none of the defaults exist, select the top 5
-                    if (!waitTypes.Any(w => w.IsSelected) && waitTypes.Count > 0)
-                    {
-                        foreach (var item in waitTypes.Take(5))
-                        {
-                            item.IsSelected = true;
-                        }
-                    }
                 }
 
                 _waitTypeItems = waitTypes;
@@ -2047,12 +2042,14 @@ private void LoadWaitStatsDetailChart(List<WaitStatsDataPoint>? data, int hoursB
             var colors = new[] {
                 ScottPlot.Colors.Blue, ScottPlot.Colors.Green, ScottPlot.Colors.Orange, ScottPlot.Colors.Red,
                 ScottPlot.Colors.Purple, ScottPlot.Colors.Cyan, ScottPlot.Colors.Magenta, ScottPlot.Colors.DarkGreen,
-                ScottPlot.Colors.Navy, ScottPlot.Colors.Brown, ScottPlot.Colors.Teal, ScottPlot.Colors.Olive
+                ScottPlot.Colors.Navy, ScottPlot.Colors.Brown, ScottPlot.Colors.Teal, ScottPlot.Colors.Olive,
+                ScottPlot.Colors.Coral, ScottPlot.Colors.SkyBlue, ScottPlot.Colors.Gold, ScottPlot.Colors.MediumPurple,
+                ScottPlot.Colors.Salmon, ScottPlot.Colors.LimeGreen, ScottPlot.Colors.SandyBrown, ScottPlot.Colors.SlateGray
             };
 
             // Get all time points across all wait types for gap filling
             int colorIndex = 0;
-            foreach (var waitType in selectedWaitTypes.Take(12)) // Limit to 12 wait types
+            foreach (var waitType in selectedWaitTypes.Take(20)) // Limit to 20 wait types
             {
                 // Get data for this wait type
                 var waitTypeData = data

Dashboard/Helpers/TabHelpers.cs

@@ -28,6 +28,72 @@ namespace PerformanceMonitorDashboard.Helpers
     /// </summary>
     public static class TabHelpers
     {
+        /// <summary>
+        /// Poison waits — always selected by default. These indicate critical resource exhaustion.
+        /// </summary>
+        public static readonly string[] PoisonWaits = new[]
+        {
+            "THREADPOOL",
+            "RESOURCE_SEMAPHORE",
+            "RESOURCE_SEMAPHORE_QUERY_COMPILE"
+        };
+
+        /// <summary>
+        /// Usual suspect waits — always selected by default. Common performance-relevant wait types.
+        /// </summary>
+        public static readonly string[] UsualSuspectWaits = new[]
+        {
+            "SOS_SCHEDULER_YIELD",
+            "CXPACKET",
+            "CXCONSUMER",
+            "PAGEIOLATCH_SH",
+            "PAGEIOLATCH_EX",
+            "WRITELOG"
+        };
+
+        /// <summary>
+        /// Prefix patterns for usual suspect waits (e.g. PAGELATCH_EX, PAGELATCH_SH, etc.)
+        /// </summary>
+        public static readonly string[] UsualSuspectPrefixes = new[] { "PAGELATCH_" };
+
+        /// <summary>
+        /// Returns the set of wait types that should be selected by default:
+        /// poison waits + usual suspects + top 10 by total wait time (deduped), capped at 12.
+        /// The availableWaitTypes list must be sorted by total wait time descending.
+        /// </summary>
+        public static HashSet<string> GetDefaultWaitTypes(IList<string> availableWaitTypes)
+        {
+            var defaults = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+            // 1. Poison waits that exist in data
+            foreach (var w in PoisonWaits)
+                if (availableWaitTypes.Contains(w)) defaults.Add(w);
+
+            // 2. Usual suspects — exact matches
+            foreach (var w in UsualSuspectWaits)
+                if (availableWaitTypes.Contains(w)) defaults.Add(w);
+
+            // 3. Usual suspects — prefix matches
+            foreach (var prefix in UsualSuspectPrefixes)
+                foreach (var w in availableWaitTypes)
+                    if (w.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
+                        defaults.Add(w);
+
+            // 4. Top 10 by total wait time (items not already in the set), hard cap at 20 total
+            int added = 0;
+            foreach (var w in availableWaitTypes)
+            {
+                if (defaults.Count >= 20) break;
+                if (added >= 10) break;
+                if (defaults.Add(w))
+                {
+                    added++;
+                }
+            }
+
+            return defaults;
+        }
+
         /// <summary>
         /// Applies the Darling Data dark theme to a ScottPlot chart.
         /// </summary>

Lite/Controls/ServerTab.xaml

@@ -125,8 +125,9 @@
                             </Grid.RowDefinitions>
                             <TextBlock Grid.Row="0" Text="Select Wait Types" FontWeight="SemiBold" Margin="0,0,0,4"/>
                             <StackPanel Grid.Row="1" Orientation="Horizontal" Margin="0,0,0,4">
-                                <Button Content="Select All" Click="WaitTypeSelectAll_Click" Padding="6,2" Margin="0,0,4,0" FontSize="11"/>
+                                <Button Content="Top Waits" Click="WaitTypeSelectAll_Click" Padding="6,2" Margin="0,0,4,0" FontSize="11"/>
                                 <Button Content="Clear All" Click="WaitTypeClearAll_Click" Padding="6,2" FontSize="11"/>
+                                <TextBlock x:Name="WaitTypeCountText" Text="0 / 20 selected" FontSize="10" Foreground="{StaticResource ForegroundMutedBrush}" VerticalAlignment="Center" Margin="8,0,0,0"/>
                             </StackPanel>
                             <TextBox Grid.Row="2" x:Name="WaitTypeSearchBox" TextChanged="WaitTypeSearch_TextChanged"
                                      Margin="0,0,0,4" Padding="4,2"/>

Lite/Controls/ServerTab.xaml.cs

@@ -50,7 +50,8 @@ public partial class ServerTab : UserControl
     {
         "#2eaef1", "#F44336", "#4CAF50", "#FFC107", "#9C27B0",
         "#FF9800", "#00BCD4", "#E91E63", "#8BC34A", "#3F51B5",
-        "#CDDC39", "#795548"
+        "#CDDC39", "#795548", "#FF7F50", "#87CEEB", "#FFD700",
+        "#9370DB", "#FA8072", "#32CD32", "#F4A460", "#708090"
     };
 
     public int UtcOffsetMinutes { get; }
@@ -988,15 +989,41 @@ private void UpdateExecutionCountTrendChart(List<QueryTrendPoint> data)
 
     /* ========== Wait Stats Picker ========== */
 
+    private static readonly string[] PoisonWaits = { "THREADPOOL", "RESOURCE_SEMAPHORE", "RESOURCE_SEMAPHORE_QUERY_COMPILE" };
+    private static readonly string[] UsualSuspectWaits = { "SOS_SCHEDULER_YIELD", "CXPACKET", "CXCONSUMER", "PAGEIOLATCH_SH", "PAGEIOLATCH_EX", "WRITELOG" };
+    private static readonly string[] UsualSuspectPrefixes = { "PAGELATCH_" };
+
+    private static HashSet<string> GetDefaultWaitTypes(List<string> availableWaitTypes)
+    {
+        var defaults = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        foreach (var w in PoisonWaits)
+            if (availableWaitTypes.Contains(w)) defaults.Add(w);
+        foreach (var w in UsualSuspectWaits)
+            if (availableWaitTypes.Contains(w)) defaults.Add(w);
+        foreach (var prefix in UsualSuspectPrefixes)
+            foreach (var w in availableWaitTypes)
+                if (w.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
+                    defaults.Add(w);
+        int added = 0;
+        foreach (var w in availableWaitTypes)
+        {
+            if (defaults.Count >= 20) break;
+            if (added >= 10) break;
+            if (!defaults.Contains(w)) { defaults.Add(w); added++; }
+        }
+        return defaults;
+    }
+
     private bool _isUpdatingWaitTypeSelection;
 
     private void PopulateWaitTypePicker(List<string> waitTypes)
     {
         var previouslySelected = new HashSet<string>(_waitTypeItems.Where(i => i.IsSelected).Select(i => i.DisplayName));
+        var topWaits = previouslySelected.Count == 0 ? GetDefaultWaitTypes(waitTypes) : null;
         _waitTypeItems = waitTypes.Select(w => new SelectableItem
         {
             DisplayName = w,
-            IsSelected = previouslySelected.Contains(w) || (previouslySelected.Count == 0 && waitTypes.IndexOf(w) < 10)
+            IsSelected = previouslySelected.Contains(w) || (topWaits != null && topWaits.Contains(w))
         }).ToList();
         /* Sort checked items to top, then preserve original order (by total wait time desc) */
         RefreshWaitTypeListOrder();
@@ -1007,9 +1034,20 @@ private void RefreshWaitTypeListOrder()
         if (_waitTypeItems == null) return;
         _waitTypeItems = _waitTypeItems
             .OrderByDescending(x => x.IsSelected)
-            .ThenBy(x => _waitTypeItems.IndexOf(x))
+            .ThenBy(x => x.DisplayName)
             .ToList();
         ApplyWaitTypeFilter();
+        UpdateWaitTypeCount();
+    }
+
+    private void UpdateWaitTypeCount()
+    {
+        if (_waitTypeItems == null || WaitTypeCountText == null) return;
+        int count = _waitTypeItems.Count(x => x.IsSelected);
+        WaitTypeCountText.Text = $"{count} / 20 selected";
+        WaitTypeCountText.Foreground = count >= 20
+            ? new SolidColorBrush((System.Windows.Media.Color)ColorConverter.ConvertFromString("#E57373")!)
+            : (System.Windows.Media.Brush)FindResource("ForegroundMutedBrush");
     }
 
     private void ApplyWaitTypeFilter()
@@ -1027,15 +1065,10 @@ private void ApplyWaitTypeFilter()
     private void WaitTypeSelectAll_Click(object sender, RoutedEventArgs e)
     {
         _isUpdatingWaitTypeSelection = true;
-        var visible = (WaitTypesList.ItemsSource as IEnumerable<SelectableItem>)?.ToList() ?? _waitTypeItems;
-        int count = visible.Count(i => i.IsSelected);
-        foreach (var item in visible)
+        var topWaits = GetDefaultWaitTypes(_waitTypeItems.Select(x => x.DisplayName).ToList());
+        foreach (var item in _waitTypeItems)
         {
-            if (!item.IsSelected && count < 12)
-            {
-                item.IsSelected = true;
-                count++;
-            }
+            item.IsSelected = topWaits.Contains(item.DisplayName);
         }
         _isUpdatingWaitTypeSelection = false;
         RefreshWaitTypeListOrder();
@@ -1063,7 +1096,7 @@ private async System.Threading.Tasks.Task UpdateWaitStatsChartFromPickerAsync()
     {
         try
         {
-            var selected = _waitTypeItems.Where(i => i.IsSelected).Take(12).ToList();
+            var selected = _waitTypeItems.Where(i => i.IsSelected).Take(20).ToList();
 
             ClearChart(WaitStatsChart);
             ApplyDarkTheme(WaitStatsChart);