Release v2.8.0 (erikdarlingdata#878)

* Implements erikdarlingdata#843 in Lite

* Implements erikdarlingdata#843 for Full Dashboard

* Add trailing newlines to ScrollPanBehavior files

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Harden DuckDB queries: parameterize values, escape paths, fix IsArchiving race

Addresses security findings from erikdarlingdata#840:
- erikdarlingdata#846: Escape single quotes in file paths interpolated into read_parquet() and COPY TO
- erikdarlingdata#847: Use DuckDB $1 parameters for DateTime values instead of string interpolation
- erikdarlingdata#849: Make IsArchiving volatile-backed to prevent stale reads across threads

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Encrypt webhook URLs with DPAPI via Windows Credential Manager

Moves Teams and Slack webhook URLs from plaintext settings.json/preferences.json
to Windows Credential Manager (DPAPI-encrypted), matching the existing pattern
used for SMTP passwords and SQL Server credentials.

Includes automatic migration: on first settings load, any plaintext URLs are
moved to Credential Manager and removed from the JSON file.

Closes erikdarlingdata#848

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Lazy-load server tabs: only load visible tab on open, full-load on first visit

Initial tab open and Refresh button now only load the currently visible tab.
First switch to any tab triggers a full refresh of that tab (all sub-tabs).
Subsequent refreshes only hit the active sub-tab.

Ctrl+Click on Refresh Tab (or Ctrl+F5) refreshes all tabs at once.
Apply to All Tabs retains existing full-refresh behavior.

Fixes erikdarlingdata#835 — prevents heavy queries (e.g. GetQueryStatsAsync) from running
on tab open when the user is only viewing Overview.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Cap query/procedure/query store grid results to TOP 500

GetQueryStatsAsync, GetProcedureStatsAsync, and GetQueryStoreDataAsync
were returning unbounded result sets. With 49 databases and 742K rows
in query_stats over 3 days, the GROUP BY with plan XML could produce
thousands of rows and timeout after 120 seconds.

TOP 500 ordered by avg CPU desc is plenty for a grid view and prevents
the query from consuming unbounded memory on large installations.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Remove pointless WAITFOR DECOMPRESS filters from stats/store queries

The CAST(DECOMPRESS(...)) NOT LIKE N'WAITFOR%' filter was decompressing
query text on every row in query_stats and query_store_data just to skip
WAITFOR queries. WAITFOR has no plan and no meaningful stats — it only
matters in query snapshots (active sessions), where the filter remains.

On a 742K-row query_stats table, this was a significant contributor to
the 120-second query timeouts reported in erikdarlingdata#835.

The snapshot filters (report.query_snapshots) and MCP phased queries
are untouched — they filter after TOP on already-hydrated text.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Refactor query/procedure/query store stats to phased DECOMPRESS approach

All three grid queries now use a 3-phase pattern:
1. Aggregate numerics into temp table (no DECOMPRESS)
2. Sum across lifetimes, rank TOP 500
3. OUTER APPLY to decompress text/plan for only the 500 winners

On a 742K-row query_stats table, this reduces DECOMPRESS calls from
742K to 500 — eliminating the 16+ minute query times reported in erikdarlingdata#835.

Matches the existing phased pattern used by the MCP query tools.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix FinOps TDE recommendation on SQL Server 2019+ (erikdarlingdata#854)

TDE moved to Standard Edition in SQL 2019, so dm_db_persisted_sku_features
no longer reports it as Enterprise-only. Add version check to give
version-appropriate licensing guidance instead of falsely claiming no
databases use TDE.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Sync PlanAnalyzer and BenefitScorer from PerformanceStudio (Apr 9-16)

Port PS PRs erikdarlingdata#216, erikdarlingdata#217, erikdarlingdata#219, erikdarlingdata#224, erikdarlingdata#229, erikdarlingdata#230, erikdarlingdata#231 to PM.

PlanAnalyzer changes:
- Rule 5: Suppress for Key Lookups (point lookups mislead per-execution estimates)
- Rule 8: Enhanced parallel skew with batch mode sort detection and practical context
- Rule 9: Large memory grant shows top 3 consumers sorted by row count
- Rule 10: Key lookup overhaul — show output columns, check predicate filtering, softer advice
- Rules 11/12/29: Suppress on 0-execution nodes (operator never ran)
- Rule 11: I/O wait severity elevation when scan hits disk
- Rule 24: FormatNodeRef helper includes object name for data access operators
- Rule 26: Suppress when row goal prediction was correct, specific cause detection
- Wait stats: DescribeWaitType with full wait type coverage, multi-wait summary
- New helpers: GetWaitLabel, HasSignificantIoWaits, IdentifyRowGoalCause, FormatNodeRef
- GetOperatorOwnElapsedMs changed to internal for BenefitScorer access

BenefitScorer (new file):
- Stage 1: MaxBenefitPercent for operator-level rules (filter, spill, lookup, etc.)
- Stage 2: Wait stats benefit scoring with parallel allocation (Joe's formula)

PlanModels additions:
- MaxBenefitPercent and ActionableFix on PlanWarning
- WaitBenefit class and WaitBenefits list on PlanStatement

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fall back to single-database mode when Azure master is inaccessible (erikdarlingdata#857)

On Azure SQL DB, some logins (e.g. Microsoft Dynamics 365 FO) are granted
access only to a specific user database and not to master. The three
collectors that enumerate databases via master — query_stats,
database_size_stats, file_io_stats — would fail the first time and
produce an empty screen.

GetAzureDatabaseListAsync now catches known access-denied/login-failed
errors from the master connection, caches the per-server decision, and
returns the connection's InitialCatalog as a single-element list. The
three callers already loop per-database, so single-DB mode works without
further changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Add nonclustered indexes for query/procedure/query store lookups

Phase 3 OUTER APPLY hydration of compressed query_text/plan_text was forcing
an Eager Index Spool over the full collect.query_stats table (and similar
for procedure_stats / query_store_data), which took 104 seconds on a
742K-row table in erikdarlingdata#835.

Changes:
- Remove CONVERT(binary(8), nvarchar-hash, 1) anti-pattern from OUTER APPLY
  WHERE clauses by keeping query_hash as native binary(8) in temp tables.
  query_hash is only converted to nvarchar(20) in the final output projection.
- Add three nonclustered indexes (install script and upgrade script):
    IX_query_stats_hash_lookup (query_hash, database_name, collection_time DESC)
    IX_procedure_stats_name_lookup (database_name, schema_name, object_name, collection_time DESC)
    IX_query_store_data_id_lookup (database_name, query_id, collection_time DESC)
- Indexes use SORT_IN_TEMPDB = ON and DATA_COMPRESSION = PAGE.
- ONLINE = ON is applied conditionally via dynamic SQL based on
  SERVERPROPERTY('EngineEdition') — Enterprise/Developer/Azure only, since
  Standard/Web/Express don't support online index operations.

Tested against CADelete's 742K-row table: Phase 3 went from 104s to
well under 1s (5s total for the full three-phase query).

Fixes erikdarlingdata#835

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Scope query snapshots to current database on Azure SQL DB (erikdarlingdata#857)

On Azure SQL Database, logins without access to master can't resolve
cross-database rows returned by sys.dm_exec_requests, which caused the
Live Snapshot button and the query snapshots collector to error in
D365FO-style environments (reported by @TrudAX in erikdarlingdata#857 after PR erikdarlingdata#858).

BuildQuerySnapshotsQuery now takes an isAzureSqlDatabase flag and emits
AND der.database_id = DB_ID() only when true. Boxed SQL Server, MI, and
elastic pool behavior is unchanged. The Live Snapshot button path gets
the flag through a new ServerTab constructor parameter wired from the
cached ServerConnectionStatus.SqlEngineEdition.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Polish Lite chart axes and sub-tab styling

- Chart X-axis prints the date line only on the first tick and on ticks
  where the date changes; all other ticks show time only. Format respects
  current culture (en-GB → dd/MM, de-DE → dd.MM, 24h clocks, etc.).
  Implemented as a DateTimeTicksBottomDateChange() extension in
  Lite/Helpers/AxesExtensions.cs and applied to every DateTimeTicksBottom
  call site in ServerTab and CorrelatedTimelineLanesControl.
- Server name no longer duplicated in the ServerTab header status line;
  ConnectionStatusText now shows just "Connecting..." / "Last refresh: ...".
- Chart tick label font bumped from 12 to 13 for readability.
- New SubTabItemStyle (thin accent underline, transparent background) in
  all three themes, applied to Queries / Memory / File I/O / Blocking /
  Perfmon / Running Jobs sub-TabControls so sub-tab selection no longer
  looks identical to main-tab selection.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Port Lite chart/tab polish to Dashboard + LSP diagnostics cleanup

Dashboard polish (ports the same items merged to Lite in erikdarlingdata#862):
- New Dashboard/Helpers/AxesExtensions.cs with DateTimeTicksBottomDateChange(),
  culture-aware (dd/MM for en-GB, dd.MM for de-DE, 24h clocks, etc.). All 52
  call sites of DateTimeTicksBottom() across 10 files swapped to use it.
- TabHelpers.ApplyTheme + ReapplyAxisColors bump chart tick label font from
  12 to 13 so numbers read cleaner on wide charts.
- SubTabItemStyle added to Dark / Light / CoolBreeze themes: thin accent
  underline + transparent background instead of filled cyan, so sub-tabs
  don't look identical to main tabs when selected. Wired via
  ItemContainerStyle on 11 sub-TabControls (Overview's inner tabs,
  Collection Health's inner tabs, Locking, ConfigChanges, CurrentConfig,
  FinOps, Memory, ResourceMetrics ×2, SystemEvents, QueryPerformance).

LSP diagnostics cleanup (tracked work from chore/lsp-diagnostics-cleanup):
- Small nullability/warning fixes across Dashboard and Lite services,
  analysis helpers, and BenefitScorer / PlanAnalyzer.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Fix Overview crosshair disappearing after tab switches / layout passes

Root cause: the control wired `Unloaded += ...Dispose()` on the crosshair
manager, and WPF fires Unloaded for transient reasons (tab virtualization,
layout rebuilds, etc.), not just when the control is actually going away.
Dispose() clears the manager's lane list, after which ReattachVLines runs
over an empty list and the crosshair is gone permanently.

Changes:
- Remove the Unloaded → Dispose() handler in both Lite and Dashboard copies.
  The manager holds only managed state (a Popup + lane references) — GC
  will clean it up with the control.
- Remove the now-redundant `_isRefreshing` flag from CorrelatedCrosshairManager.
  The `lane.VLine == null` check in OnMouseMove is a sufficient "not ready"
  guard and is self-healing once VLines are recreated.
- Wrap ReattachVLines in a try/finally on the control side, with a new
  idempotent EnsureVLinesAttached() safety net that only creates VLines
  for lanes where they're still null.
- Make CreateVLine catch per-lane exceptions so one failing chart can't
  prevent the others from recovering.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Fix Memory Pressure Events chart filter; add MCP interpretation (erikdarlingdata#865)

Chart previously filtered to HIGH severity only (indicator>=3), which on most
servers never fires, producing an empty chart even when sp_pressuredetector-
level medium pressure (indicator=2) was occurring constantly. Switch to stacked
bars per hour, split by SQL Server (process) vs Operating System (system), with
severe events capped on top of medium in a darker shade. Extend ChartHoverHelper
to support BarPlot tooltips. Add MCP guidance for interpreting indicator values
and routing to the right follow-up tool.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Port Memory Pressure Events feature to Lite (erikdarlingdata#865)

Lite was missing the RING_BUFFER_RESOURCE_MONITOR collector entirely — no
collector, no table, no chart, no MCP tool. This adds the full feature:

- Schema: new memory_pressure_events table + index, schema v25, added to
  ArchivableTables, server-id-fix list, and ArchiveService.
- Collector: CollectMemoryPressureEventsAsync queries the ring buffer and
  client-side-dedupes against DuckDB's MAX(sample_time). Azure SQL DB returns
  zero rows (ring buffer not exposed there). Scheduled every 5 min (Aggressive
  and Balanced presets) or 15 min (Low-Impact).
- UI: new 'Memory Pressure Events' sub-tab on the Memory tab with the same
  stacked-bar chart as Dashboard (SQL Server medium/severe, Operating System
  medium/severe). Wired into full-load and sub-tab-switch refresh paths.
- Hover: ported the BarPlot support from Dashboard's ChartHoverHelper so bar
  tooltips work and report the correct segment height for stacked bars.
- MCP: new get_memory_pressure_events tool + the 'Interpreting Memory
  Pressure Events' guidance section in McpInstructions.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Bump schema table count test to 30 for memory_pressure_events

Companion update to the new memory_pressure_events table added in this PR.
SchemaStatements_MatchTableCount asserts the total table count; needs to
move from 29 to 30 to reflect the new table.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Fix blocked process report plan lookup (erikdarlingdata#867) (erikdarlingdata#868)

Right-click > View Plan on a Blocked Process Reports row silently fell
through (no handler case) and Get Actual Plan erred with "no query text."

- Split the grid onto its own BlockedProcessContextMenu with separate
  View Blocked Plan / View Blocking Plan actions; drop Get Actual Plan
  (re-executing a mid-transaction blocked query is a foot-gun).
- Parse all <frame> entries from the BPR XML's executionStack, filter
  the 42-byte all-zero sql_handle placeholder (dynamic SQL / system
  context), default stmtstart=0 / stmtend=-1 per the dm_exec_text_query_plan
  convention. Matches sp_HumanEventsBlockViewer's XPath and join shape.
- Add FetchPlanBySqlHandleAsync keyed on sql_handle + statement offsets
  against sys.dm_exec_query_stats. Caller iterates frames until one
  resolves; falls back to a clear "plan no longer in cache" message.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Pre-filter query snapshot requests into #temp on Azure SQL DB (erikdarlingdata#857) (erikdarlingdata#869)

Follow-up to erikdarlingdata#861. The DB_ID() predicate in the WHERE clause wasn't
enough — the OUTER APPLYs to sys.dm_exec_sql_text and
sys.dm_exec_text_query_plan were still being evaluated against
master-scoped rows from sys.dm_exec_requests before the filter was
applied, tripping VIEW SERVER PERFORMANCE STATE errors for DB-scoped
logins (D365FO). A CTE or derived table wouldn't guarantee the
filter order, so materialise the filtered request rows into #req
first and drive the DMFs off that.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Stop retrying collectors after non-transient permission denial (erikdarlingdata#857) (erikdarlingdata#870)

The collector loop already classifies SQL errors 229 / 297 / 300 as
PERMISSIONS status and excludes them from the failure rate, but it
keeps re-running the collector every interval and logging an
identical denial each time. For DB-scoped logins on Azure SQL DB
(e.g. D365FO) this churns the collection log and gives no new
information — the permission won't change mid-session.

Flag the collector on first denial and short-circuit RunCollectorAsync
so we don't make the round-trip or the log entry. Flag is in-memory
per (server, collector) — cleared on app restart so newly granted
permissions are picked up on the next launch.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Skip live query plans on Azure SQL DB (erikdarlingdata#857) (erikdarlingdata#871)

sys.dm_exec_query_statistics_xml requires VIEW SERVER PERFORMANCE
STATE on Azure SQL Database regardless of scope, so DB-scoped logins
(e.g. D365FO) still hit error 300 even after the #temp pre-filter
landed in erikdarlingdata#869. The OUTER APPLY evaluates the DMF for every session
in #req and fails on the permission check before returning rows.

Force supportsLiveQueryPlan=false for SqlEngineEdition=5 in both the
collector and the Live Snapshot button paths. Boxed SQL Server and
Azure MI (edition 8) still get live plans as before.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Fix FinOps recommendation severity sort order (erikdarlingdata#872)

Sort recommendations by severity rank (High=1, Medium=2, Low=3)
instead of alphabetically. Adds SeveritySort property to
RecommendationRow and uses it as SortMemberPath for the Severity
column. Display strings are unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Fix FinOps severity sort order in Dashboard (erikdarlingdata#872)

Severity column was sorting alphabetically (High, Low, Medium) instead
of by severity ranking. Added SeveritySort computed property on
FinOpsRecommendation, ordered results by it, and wired the DataGrid
column's SortMemberPath so click-sort matches the default order.

Mirrors the Lite fix in PR erikdarlingdata#874.

* Drop sys.dm_os_schedulers from memory_stats on Azure SQL DB (erikdarlingdata#857) (erikdarlingdata#876)

Azure SQL Database DBs hosted in an elastic pool (notably D365FO
customer tenants) enforce VIEW SERVER PERFORMANCE STATE on
sys.dm_os_schedulers regardless of the login's DB-scoped grants —
VIEW DATABASE STATE + VIEW DATABASE PERFORMANCE STATE on the user DB
are not sufficient. Verified by reproducing the failure in a
standard Azure SQL DB elastic pool with a contained DB user; bare
sys.dm_exec_requests/sys.dm_os_sys_info/sys.dm_os_performance_counters
succeed but sys.dm_os_memory_clerks / sys.dm_os_schedulers /
sys.dm_os_waiting_tasks fail with error 300.

The other failing collectors (memory_clerks, waiting_tasks,
tempdb_stats) have no DB-scoped alternative and will stay skip-gated
via erikdarlingdata#870 for these users.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Release v2.8.0: version bumps and changelog (erikdarlingdata#877)

Adds nonclustered indexes to collect.query_stats, procedure_stats, and
query_store_data for Dashboard grid lookups (erikdarlingdata#835). Ports Memory Pressure
Events to Lite (erikdarlingdata#865). Multiple Azure SQL DB collector fixes (erikdarlingdata#857).
FinOps severity sort order fix (erikdarlingdata#872). Grid auto-scrolling (erikdarlingdata#843).

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Scope v2.8.0 webhook DPAPI note to Dashboard (erikdarlingdata#879)

Lite webhook URLs still read from plaintext settings — avoids implying
the security hardening shipped to both editions.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: ClaudioESSilva <claudiosil100@gmail.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 3 people

CHANGELOG.md

@@ -5,6 +5,49 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2.8.0] - TBD
+
+### Important
+
+- **New nonclustered indexes** on `collect.query_stats`, `collect.procedure_stats`, and `collect.query_store_data` to eliminate Eager Index Spools in Dashboard grid queries. On large installations these indexes may take several minutes to build; the upgrade script uses `ONLINE = ON` on Enterprise/Developer/Azure editions and falls back to offline on Standard/Web ([#835])
+
+### Added
+
+- **Memory Pressure Events in Lite** — the collector, chart, and `get_memory_pressure_events` MCP tool previously only in the Full Edition are now available in Lite ([#865])
+- **Grid auto-scrolling** in Lite and Dashboard ([#843]) — thanks [@ClaudioESSilva](https://github.com/ClaudioESSilva)
+
+### Changed
+
+- **PlanAnalyzer and BenefitScorer** synced with PerformanceStudio's Apr 9–16 improvements
+- **Query/Procedure/Query Store stats** refactored to a phased DECOMPRESS approach; removed unhelpful `WAITFOR DECOMPRESS` filters
+- **Query/Procedure/Query Store grids** capped to TOP 500 to prevent UI freezes on large datasets
+- **Server tabs lazy-load** — only the visible server tab loads on startup; remaining tabs load on first visit
+- **Webhook URLs (Dashboard)** encrypted with DPAPI via Windows Credential Manager — Lite webhook URLs remain in plaintext settings for now
+- **DuckDB queries hardened** — parameterized values, escaped paths, fixed `IsArchiving` race
+- **Lite chart axes and sub-tab styling** polished, then ported to Dashboard
+
+### Fixed
+
+- **Memory Pressure Events chart filter** was dropping valid rows; added MCP interpretation guidance ([#865])
+- **FinOps recommendation severity sort order** in Lite and Dashboard ([#872])
+- **Overview crosshair** disappearing after tab switches or layout passes
+- **Blocked process report plan lookup** returning the wrong plan ([#867])
+- **FinOps TDE recommendation** flagging Standard edition on SQL Server 2019+ where TDE is free ([#854])
+- **Azure SQL DB collector** falls back to single-database mode when `master` is inaccessible ([#857])
+- **Azure SQL DB query snapshots** scoped to the current database ([#857])
+- **Azure SQL DB query snapshot prefilter** — request set is narrowed into `#temp` before joining DMVs to avoid Azure-specific execution plan issues ([#857])
+- **Azure SQL DB live query plans** — now skipped gracefully instead of erroring ([#857])
+- **Azure SQL DB memory_stats collector** — dropped `sys.dm_os_schedulers` which is blocked on elastic-pool contained users regardless of DB-scoped grants ([#857])
+- **Non-transient permission denials** now stop collector retries instead of looping forever ([#857])
+
+[#835]: https://github.com/erikdarlingdata/PerformanceMonitor/issues/835
+[#843]: https://github.com/erikdarlingdata/PerformanceMonitor/issues/843
+[#854]: https://github.com/erikdarlingdata/PerformanceMonitor/issues/854
+[#857]: https://github.com/erikdarlingdata/PerformanceMonitor/issues/857
+[#865]: https://github.com/erikdarlingdata/PerformanceMonitor/issues/865
+[#867]: https://github.com/erikdarlingdata/PerformanceMonitor/issues/867
+[#872]: https://github.com/erikdarlingdata/PerformanceMonitor/issues/872
+
 ## [2.7.0] - 2026-04-13
 
 ### Added

Dashboard/Analysis/SqlServerBaselineProvider.cs

@@ -463,7 +463,7 @@ private static double PoolVariance(List<BaselineBucket> buckets, double grandMea
         return totalSumSq / (totalSamples - 1);
     }
 
-    private class CachedBaseline
+    private sealed class CachedBaseline
     {
         public DateTime ComputedAt { get; init; }
         public DateTime RealTime { get; init; }

Dashboard/Controls/ConfigChangesContent.xaml

@@ -15,7 +15,7 @@
             <MenuItem Header="Export to CSV..." Click="ExportToCsv_Click"/>
         </ContextMenu>
     </UserControl.Resources>
-    <TabControl>
+    <TabControl ItemContainerStyle="{DynamicResource SubTabItemStyle}">
         <!-- Server Configuration Changes Sub-Tab -->
         <TabItem Header="Server Config Changes">
             <Grid>

Dashboard/Controls/CorrelatedTimelineLanesControl.xaml.cs

@@ -31,7 +31,12 @@ public partial class CorrelatedTimelineLanesControl : UserControl
     public CorrelatedTimelineLanesControl()
     {
         InitializeComponent();
-        Unloaded += (_, _) => _crosshairManager?.Dispose();
+        /* No Unloaded → Dispose() handler: WPF fires Unloaded for transient
+           reasons (tab virtualization, layout rebuilds) and Dispose() clears
+           the crosshair manager's lane list, permanently breaking the crosshair
+           until the ServerTab is rebuilt. The manager holds only managed state
+           (a Popup + lane references) — letting GC clean it up with the control
+           is fine. */
     }
 
     /// <summary>
@@ -69,6 +74,9 @@ public async Task RefreshAsync(int hoursBack, DateTime? fromDate, DateTime? toDa
 
         _crosshairManager?.PrepareForRefresh();
 
+        try
+        {
+
         var cpuTask = _dataService.GetCpuUtilizationAsync(hoursBack, fromDate, toDate);
         var waitTask = _dataService.GetTotalWaitStatsTrendAsync(hoursBack, fromDate, toDate);
         var blockingTask = _dataService.GetBlockedSessionTrendAsync(hoursBack, fromDate, toDate);
@@ -225,8 +233,18 @@ public async Task RefreshAsync(int hoursBack, DateTime? fromDate, DateTime? toDa
             _crosshairManager?.SetComparisonLabel(ComparisonLabel(comparisonRange.Value, fromDate, hoursBack));
         }
 
+        /* VLines must be re-attached before SyncXAxes so they're part of
+           the render set when the chart refreshes. */
         _crosshairManager?.ReattachVLines();
         SyncXAxes(hoursBack, fromDate, toDate);
+        }
+        finally
+        {
+            /* Safety net: if something threw between PrepareForRefresh() and the
+               ReattachVLines() call above, VLines are still null. EnsureVLinesAttached
+               creates them only for lanes where VLine is null, so it's idempotent. */
+            _crosshairManager?.EnsureVLinesAttached();
+        }
     }
 
     /// <summary>
@@ -320,7 +338,7 @@ private void UpdateBlockingLane(List<(double Time, double Value)> blockingData,
             }
         }
 
-        BlockingChart.Plot.Axes.DateTimeTicksBottom();
+        BlockingChart.Plot.Axes.DateTimeTicksBottomDateChange();
         BlockingChart.Plot.Axes.Bottom.TickLabelStyle.IsVisible = false;
         TabHelpers.ReapplyAxisColors(BlockingChart);
 
@@ -394,7 +412,7 @@ private void UpdateLane(ScottPlot.WPF.WpfPlot chart, string title,
 
         _crosshairManager?.SetLaneData(chart, times, values);
 
-        chart.Plot.Axes.DateTimeTicksBottom();
+        chart.Plot.Axes.DateTimeTicksBottomDateChange();
         if (chart != FileIoChart)
             chart.Plot.Axes.Bottom.TickLabelStyle.IsVisible = false;
 

Dashboard/Controls/CurrentConfigContent.xaml

@@ -15,7 +15,7 @@
             <MenuItem Header="Export to CSV..." Click="ExportToCsv_Click"/>
         </ContextMenu>
     </UserControl.Resources>
-    <TabControl>
+    <TabControl ItemContainerStyle="{DynamicResource SubTabItemStyle}">
         <!-- Current Server Configuration Sub-Tab -->
         <TabItem Header="Server Configuration">
             <Grid>

Dashboard/Controls/FinOpsContent.xaml

@@ -44,7 +44,7 @@
                       SelectionChanged="ServerSelector_SelectionChanged"/>
         </StackPanel>
 
-        <TabControl Grid.Row="1" Background="Transparent" BorderThickness="0">
+        <TabControl Grid.Row="1" Background="Transparent" BorderThickness="0" ItemContainerStyle="{DynamicResource SubTabItemStyle}">
 
         <!-- Recommendations Sub-Tab -->
         <TabItem Header="Recommendations">
@@ -90,7 +90,7 @@
                                 </StackPanel>
                             </DataGridTextColumn.Header>
                         </DataGridTextColumn>
-                        <DataGridTextColumn Binding="{Binding Severity}" MinWidth="80" Width="Auto">
+                        <DataGridTextColumn Binding="{Binding Severity}" SortMemberPath="SeveritySort" MinWidth="80" Width="Auto">
                             <DataGridTextColumn.Header>
                                 <StackPanel Orientation="Horizontal">
                                     <Button Style="{DynamicResource ColumnFilterButtonStyle}" Tag="Severity" Click="FinOpsFilter_Click" Margin="0,0,4,0"/>

Dashboard/Controls/MemoryContent.xaml

@@ -32,7 +32,7 @@
         </ResourceDictionary>
     </UserControl.Resources>
 
-    <TabControl x:Name="SubTabControl" TabStripPlacement="Top" Margin="0,5,0,0">
+    <TabControl x:Name="SubTabControl" TabStripPlacement="Top" Margin="0,5,0,0" ItemContainerStyle="{DynamicResource SubTabItemStyle}">
         <!-- Memory Overview Sub-Tab -->
         <TabItem Header="Memory Overview">
             <!-- Chart + Summary Panel (grid removed) -->