Re-show a closed tool pane on Analyze / Show Search

ShowToolPane only activated panes still in the layout, so once the user closed the Analyzer panel (Dock removes the pane and collapses its now-empty dock) Analyze became a silent no-op -- the entity was added but the panel never reappeared. ShowToolPane now finds-or-rebuilds the pane's home ToolDock at its alignment, splicing it back into the layout where CreateLayout would have placed it, then adds and activates the pane. This same materialize-on-demand path is what lets panes be hidden by default.

ILSpy.Tests/Analyzers/AnalyzerPaneVisibilityTests.cs

@@ -0,0 +1,78 @@
+// Copyright (c) 2026 AlphaSierraPapa for the SharpDevelop Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+using Avalonia.Headless.NUnit;
+
+using AwesomeAssertions;
+
+using Dock.Model.Core;
+
+using ILSpy.Analyzers;
+using ILSpy.AppEnv;
+using ILSpy.Docking;
+
+using NUnit.Framework;
+
+namespace ICSharpCode.ILSpy.Tests.Analyzers;
+
+[TestFixture]
+public class AnalyzerPaneVisibilityTests
+{
+	static IEnumerable<IDockable> AllDockables(IDockable? root)
+	{
+		if (root is null)
+			yield break;
+		yield return root;
+		if (root is IDock dock && dock.VisibleDockables is { } kids)
+			foreach (var k in kids)
+				foreach (var d in AllDockables(k))
+					yield return d;
+	}
+
+	[AvaloniaTest]
+	public async Task Analyze_Reopens_The_Analyzer_Pane_After_The_User_Closed_It()
+	{
+		// Repro for "Analyze does not make the Analyzer panel visible": the user closes the
+		// bottom Analyzer panel, then Analyze must bring it back. ShowToolPane only activated
+		// panes still in the layout, so a closed pane (removed from VisibleDockables) could
+		// never be restored -- Analyze became a silent no-op.
+		var (_, vm) = await TestHarness.BootAsync(3);
+		var dockWorkspace = AppComposition.Current.GetExport<DockWorkspace>();
+		var analyzer = AppComposition.Current.GetExport<AnalyzerTreeViewModel>();
+		var factory = (ILSpyDockFactory)dockWorkspace.Factory;
+
+		AllDockables(dockWorkspace.Layout).Should().Contain(analyzer,
+			"baseline: the analyzer pane is in the default layout");
+
+		// The user closes the bottom Analyzer panel (its close button calls CloseDockable).
+		factory.CloseDockable(analyzer);
+		AllDockables(dockWorkspace.Layout).Should().NotContain(analyzer,
+			"closing removes the analyzer pane from the layout");
+
+		// Analyze -> ShowToolPane must restore the closed pane and activate it.
+		dockWorkspace.ShowToolPane(AnalyzerTreeViewModel.PaneContentId);
+
+		AllDockables(dockWorkspace.Layout).Should().Contain(analyzer,
+			"Analyze must restore the closed analyzer pane so the user sees the entity they added");
+		(analyzer.Owner as IDock)?.ActiveDockable.Should().BeSameAs(analyzer,
+			"the restored pane must be the active dockable in its dock");
+	}
+}

ILSpy/Docking/DockWorkspace.cs

@@ -1045,24 +1045,13 @@ namespace ILSpy.Docking
 		/// selection across — setting it after-the-fact misses the activation event.
 		/// </param>
 		/// <summary>
-		/// Brings the tool pane with the given <paramref name="contentId"/> to focus. Walks
-		/// every <see cref="IDockable"/> in the layout via <see cref="GetAllDockables"/> and
-		/// matches on <see cref="IDockable.Id"/>. Silently no-ops when the pane isn't in the
-		/// layout — e.g. it was closed via its X button and hasn't been re-added.
+		/// Brings the tool pane with the given <paramref name="contentId"/> into view and
+		/// activates it. Delegates to <see cref="ILSpyDockFactory.ShowToolPane"/>, which
+		/// re-materialises the pane (and recreates its home dock) when it was closed or is hidden
+		/// by default -- so "Show Search" / "Analyze" reliably reveal the pane even after the user
+		/// closed it.
 		/// </summary>
-		public void ShowToolPane(string contentId)
-		{
-			foreach (var dockable in GetAllDockables(Layout))
-			{
-				if (dockable is ToolPaneModel toolPane && toolPane.Id == contentId)
-				{
-					factory.SetActiveDockable(toolPane);
-					if (toolPane.Owner is IDock owner)
-						factory.SetFocusedDockable(owner, toolPane);
-					return;
-				}
-			}
-		}
+		public void ShowToolPane(string contentId) => factory.ShowToolPane(contentId);
 
 		void ExecuteShowSearch()
 		{
@@ -1084,21 +1073,6 @@ namespace ILSpy.Docking
 			}
 		}
 
-		static System.Collections.Generic.IEnumerable<IDockable> GetAllDockables(IDockable? root)
-		{
-			if (root == null)
-				yield break;
-			yield return root;
-			if (root is IDock dock && dock.VisibleDockables != null)
-			{
-				foreach (var child in dock.VisibleDockables)
-				{
-					foreach (var descendant in GetAllDockables(child))
-						yield return descendant;
-				}
-			}
-		}
-
 		public ContentTabPage OpenNewTab(ContentPageModel content, SharpTreeNode? sourceNode = null)
 		{
 			// Carve-outs are born frozen — they survive tree-node selections instead of

ILSpy/Docking/ILSpyDockFactory.cs

@@ -447,5 +447,109 @@ namespace ILSpy.Docking
 				remaining -= right.Proportion;
 			return remaining > 0 ? remaining : 0.5;
 		}
+
+		static (string Id, Alignment DockAlignment, double Proportion) ToolDockSpec(ToolPaneAlignment alignment)
+			=> alignment switch {
+				ToolPaneAlignment.Left => ("LeftTools", Alignment.Left, 0.25),
+				ToolPaneAlignment.Right => ("RightTools", Alignment.Right, 0.25),
+				ToolPaneAlignment.Top => ("TopTools", Alignment.Top, 0.2),
+				_ => ("BottomTools", Alignment.Bottom, 0.2),
+			};
+
+		/// <summary>
+		/// Brings a tool pane into view: activates it if it is already shown, otherwise
+		/// materialises it -- (re)creating its home <see cref="ToolDock"/> at the pane's
+		/// alignment and splicing that dock back into the layout if it was never built or was
+		/// removed when the user closed its last pane. This is the single entry point both for
+		/// "Show Search / Analyze" and for revealing a pane that is hidden by default.
+		/// Returns the pane, or null when <paramref name="contentId"/> matches no registered pane.
+		/// </summary>
+		public ToolPaneModel? ShowToolPane(string contentId)
+		{
+			var entry = panes.FirstOrDefault(e => string.Equals(e.Pane.Id, contentId, StringComparison.Ordinal));
+			if (entry?.Pane is not { } pane)
+				return null;
+
+			// Already live in the layout -> just activate it where it sits.
+			if (pane.Owner is IDock current && current.VisibleDockables?.Contains(pane) == true)
+			{
+				SetActiveDockable(pane);
+				SetFocusedDockable(current, pane);
+				return pane;
+			}
+
+			var dock = FindOrCreateToolDock(entry.Metadata.Alignment);
+			if (dock is null)
+				return pane;
+			AddDockable(dock, pane);
+			SetActiveDockable(pane);
+			SetFocusedDockable(dock, pane);
+			return pane;
+		}
+
+		// Finds the live ToolDock for an alignment, or builds an empty one and splices it into the
+		// layout at the same position CreateLayout would have (top/bottom inside the documents'
+		// vertical column; left/right inside the outer horizontal row), separated by a splitter.
+		ToolDock? FindOrCreateToolDock(ToolPaneAlignment alignment)
+		{
+			var (id, dockAlignment, proportion) = ToolDockSpec(alignment);
+
+			var root = GetRootDock();
+			if (root != null)
+			{
+				var existing = Flatten(root).OfType<ToolDock>()
+					.FirstOrDefault(t => t.Alignment == dockAlignment);
+				if (existing != null)
+					return existing;
+			}
+
+			// vertical = the documents' column (top/bottom siblings); horizontal = the outer row.
+			if (Documents?.Owner is not IDock vertical || vertical.VisibleDockables is null)
+				return null;
+
+			var dock = new ToolDock {
+				Id = id,
+				Proportion = proportion,
+				Alignment = dockAlignment,
+				VisibleDockables = CreateList(System.Array.Empty<IDockable>()),
+				DockCapabilityPolicy = new DockCapabilityPolicy(),
+			};
+
+			switch (alignment)
+			{
+				case ToolPaneAlignment.Bottom:
+					AddDockable(vertical, new ProportionalDockSplitter { Id = "BottomSplitter" });
+					AddDockable(vertical, dock);
+					break;
+				case ToolPaneAlignment.Top:
+					InsertDockable(vertical, new ProportionalDockSplitter { Id = "TopSplitter" }, 0);
+					InsertDockable(vertical, dock, 0);
+					break;
+				case ToolPaneAlignment.Left:
+				case ToolPaneAlignment.Right:
+					if (vertical.Owner is not IDock horizontal)
+						return null;
+					if (alignment == ToolPaneAlignment.Left)
+					{
+						InsertDockable(horizontal, new ProportionalDockSplitter { Id = "LeftSplitter" }, 0);
+						InsertDockable(horizontal, dock, 0);
+					}
+					else
+					{
+						AddDockable(horizontal, new ProportionalDockSplitter { Id = "RightSplitter" });
+						AddDockable(horizontal, dock);
+					}
+					break;
+			}
+			return dock;
+		}
+
+		IDock? GetRootDock()
+		{
+			IDockable? d = Documents;
+			while (d?.Owner is { } owner)
+				d = owner;
+			return d as IDock;
+		}
 	}
 }