diff --git a/ILSpy.Tests/Editor/DocumentationRendererTooltipWidthTests.cs b/ILSpy.Tests/Editor/DocumentationRendererTooltipWidthTests.cs
new file mode 100644
index 000000000..1906006dd
--- /dev/null
+++ b/ILSpy.Tests/Editor/DocumentationRendererTooltipWidthTests.cs
@@ -0,0 +1,97 @@
+// 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.Linq;
+
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.Headless.NUnit;
+using Avalonia.LogicalTree;
+using Avalonia.Media;
+
+using AvaloniaEdit.Highlighting;
+
+using AwesomeAssertions;
+
+using ICSharpCode.Decompiler.CSharp.OutputVisitor;
+
+using ILSpy.TextView;
+
+using NUnit.Framework;
+
+namespace ICSharpCode.ILSpy.Tests.TextView;
+
+/// <summary>
+/// Pins the rendering shape of method-signature tooltips so a long signature isn't
+/// clipped horizontally. Two failure modes the original implementation suffered from:
+/// (1) the signature <see cref="SelectableTextBlock"/> was created with
+/// <see cref="TextWrapping.NoWrap"/>, so text past the popup's MaxWidth was simply cut
+/// off (no horizontal scrolling because the outer ScrollViewer disables it);
+/// (2) the popup MaxWidth defaulted to a snug 600px, narrower than most real C#
+/// generic-method signatures. WPF parity is wrap-friendly, so we mirror that — these
+/// tests fail if either property regresses.
+/// </summary>
+[TestFixture]
+public class DocumentationRendererTooltipWidthTests
+{
+	[AvaloniaTest]
+	public void Signature_Block_Wraps_So_Long_Method_Signatures_Are_Not_Clipped()
+	{
+		var renderer = new DocumentationRenderer(
+			new CSharpAmbience(),
+			new FontFamily("Consolas, Menlo, Monospace"),
+			12);
+
+		// A real C# Zip overload — long enough that it exceeds the previous 600px cap at
+		// the popup's monospace 12pt size. The bug shows up on any method whose rendered
+		// signature is wider than the popup's outer MaxWidth.
+		var longSignature = new RichText(
+			"public static IEnumerable<TResult> Zip<TFirst, TSecond, TThird, TResult>("
+			+ "this IEnumerable<TFirst> first, IEnumerable<TSecond> second, "
+			+ "IEnumerable<TThird> third, "
+			+ "Func<TFirst, TSecond, TThird, TResult> resultSelector)");
+
+		renderer.AddSignatureBlock(longSignature);
+
+		var view = renderer.CreateView();
+		var signature = view.GetLogicalDescendants()
+			.OfType<SelectableTextBlock>()
+			.FirstOrDefault();
+		signature.Should().NotBeNull(
+			"DocumentationRenderer must materialise the signature as a SelectableTextBlock");
+		signature!.TextWrapping.Should().Be(TextWrapping.Wrap,
+			"the signature must wrap inside the popup — without wrapping a long signature is "
+			+ "clipped at the outer MaxWidth because the ScrollViewer disables horizontal scrolling");
+	}
+
+	[AvaloniaTest]
+	public void CreateView_Default_MaxWidth_Is_Generous_Enough_For_Typical_Signatures()
+	{
+		// 600 was too narrow — generic methods + ref-struct parameters routinely exceed it.
+		// Pin the bumped default so a future tweak doesn't silently shrink it back.
+		var renderer = new DocumentationRenderer(
+			new CSharpAmbience(),
+			new FontFamily("Consolas, Menlo, Monospace"),
+			12);
+
+		var view = (Border)renderer.CreateView();
+		view.MaxWidth.Should().BeGreaterThanOrEqualTo(900,
+			"the popup's outer MaxWidth must be wide enough that most realistic method "
+			+ "signatures fit without aggressive wrapping");
+	}
+}
diff --git a/ILSpy/TextView/DocumentationRenderer.cs b/ILSpy/TextView/DocumentationRenderer.cs
index aca728228..c38d4caab 100644
--- a/ILSpy/TextView/DocumentationRenderer.cs
+++ b/ILSpy/TextView/DocumentationRenderer.cs
@@ -101,7 +101,7 @@ namespace ILSpy.TextView
 		/// Wraps the accumulated content in a chrome border + scroll viewer and returns the
 		/// final control tree for use in a popup.
 		/// </summary>
-		public Control CreateView(double maxWidth = 600, double maxHeight = 400)
+		public Control CreateView(double maxWidth = 900, double maxHeight = 400)
 		{
 			FlushAddedText(true);
 
@@ -127,10 +127,15 @@ namespace ILSpy.TextView
 			FlushAddedText(true);
 			inlineCollection = null;
 
+			// Wrap rather than NoWrap so a signature wider than the popup's MaxWidth folds
+			// to multiple lines instead of being clipped at the right edge — the outer
+			// ScrollViewer disables horizontal scrolling, so NoWrap meant "the right half
+			// of long generic method signatures is invisible". WPF parity: the equivalent
+			// FlowDocument Paragraph wraps by default (Paragraph doesn't even support NoWrap).
 			var block = new SelectableTextBlock {
 				FontFamily = codeFont,
 				FontSize = fontSize,
-				TextWrapping = TextWrapping.NoWrap,
+				TextWrapping = TextWrapping.Wrap,
 				Margin = new Thickness(0, 0, 0, 6),
 				Inlines = new InlineCollection(),
 			};