diff --git a/src/Ramstack.HtmxToolkit/Configuration/HtmxConfig.cs b/src/Ramstack.HtmxToolkit/Configuration/HtmxConfig.cs
index fd4f6e7..ccd5119 100644
--- a/src/Ramstack.HtmxToolkit/Configuration/HtmxConfig.cs
+++ b/src/Ramstack.HtmxToolkit/Configuration/HtmxConfig.cs
@@ -7,6 +7,11 @@ namespace Ramstack.HtmxToolkit.Configuration;
 /// <summary>
 /// Represents configuration for a specific major version of HTMX.
 /// </summary>
+/// <remarks>
+/// Configuration JSON is cached until a configuration property is assigned.
+/// Changes made in place to arrays, collections, or their items do not invalidate the cache;
+/// reassign the containing property after making such changes.
+/// </remarks>
 public abstract class HtmxConfig
 {
     private HtmlString? _json;
@@ -28,7 +33,7 @@ internal HtmxConfig(HtmxTargetVersion version) =>
 
     /// <summary>
     /// Returns this configuration serialized as JSON. The result is
-    /// cached and reused until the configuration changes.
+    /// cached and reused until a configuration property is assigned.
     /// </summary>
     /// <returns>
     /// An <see cref="HtmlString" /> containing the configuration serialized as JSON.
diff --git a/src/Ramstack.HtmxToolkit/HtmxLocationOptions.cs b/src/Ramstack.HtmxToolkit/HtmxLocationOptions.cs
index c5d64df..0a87884 100644
--- a/src/Ramstack.HtmxToolkit/HtmxLocationOptions.cs
+++ b/src/Ramstack.HtmxToolkit/HtmxLocationOptions.cs
@@ -75,10 +75,18 @@ public HtmxSwap? Swap
     public string? Select { get; set; }
 
     /// <summary>
-    /// Gets or sets a comma-separated list of selectors, optionally followed by swap styles,
-    /// used to select content for out-of-band swaps from the response.
+    /// Gets or sets a comma-separated list of elements, each optionally followed by a colon
+    /// and a swap style, used to select content for out-of-band swaps from the response.
     /// </summary>
-    /// <remarks>Supported in HTMX 2.0.8 and later 2.x releases, and in HTMX 4.x.</remarks>
+    /// <remarks>
+    /// <para>Supported in HTMX 2.0.8 and later 2.x releases, and in HTMX 4.x.</para>
+    /// <para>
+    ///   HTMX 2.x accepts only element IDs, with or without a leading <c>#</c>,
+    ///   for example <c>#alerts,#cart:innerHTML</c>. HTMX 4.x accepts CSS selectors.
+    ///   Neither version supports IDs or selectors that contain a comma or a colon,
+    ///   such as <c>li:first-child</c>.
+    /// </para>
+    /// </remarks>
     public string? SelectOob { get; set; }
 
     /// <summary>
diff --git a/src/Ramstack.HtmxToolkit/HtmxRequestAttribute.cs b/src/Ramstack.HtmxToolkit/HtmxRequestAttribute.cs
index 6ee7899..f52b658 100644
--- a/src/Ramstack.HtmxToolkit/HtmxRequestAttribute.cs
+++ b/src/Ramstack.HtmxToolkit/HtmxRequestAttribute.cs
@@ -51,7 +51,7 @@ public bool Accept(ActionConstraintContext context)
         if (BoostedFilter == HtmxBoostedFilter.Any)
             return true;
 
-        var filter = request.IsHtmxBoosted()
+        var filter = headers.Boosted
             ? HtmxBoostedFilter.Boosted
             : HtmxBoostedFilter.NonBoosted;
 
diff --git a/src/Ramstack.HtmxToolkit/HtmxRequestCache.cs b/src/Ramstack.HtmxToolkit/HtmxRequestCache.cs
index 7ed96bf..dc32b51 100644
--- a/src/Ramstack.HtmxToolkit/HtmxRequestCache.cs
+++ b/src/Ramstack.HtmxToolkit/HtmxRequestCache.cs
@@ -8,6 +8,7 @@ public enum HtmxRequestCache
 {
     /// <summary>
     /// Uses the browser's normal HTTP cache behavior.
+    /// This is the Fetch default.
     /// </summary>
     Default,
 
diff --git a/src/Ramstack.HtmxToolkit/HtmxRequestRedirect.cs b/src/Ramstack.HtmxToolkit/HtmxRequestRedirect.cs
index a705a40..1873f82 100644
--- a/src/Ramstack.HtmxToolkit/HtmxRequestRedirect.cs
+++ b/src/Ramstack.HtmxToolkit/HtmxRequestRedirect.cs
@@ -8,6 +8,7 @@ public enum HtmxRequestRedirect
 {
     /// <summary>
     /// Follows redirects automatically.
+    /// This is the Fetch default.
     /// </summary>
     Follow,
 
diff --git a/src/Ramstack.HtmxToolkit/HttpRequestExtensions.cs b/src/Ramstack.HtmxToolkit/HttpRequestExtensions.cs
index 96cb6ce..371510f 100644
--- a/src/Ramstack.HtmxToolkit/HttpRequestExtensions.cs
+++ b/src/Ramstack.HtmxToolkit/HttpRequestExtensions.cs
@@ -58,6 +58,9 @@ public static bool IsHtmxBoosted(this HttpRequest request) =>
     /// including HTMX 1.x and 2.x requests without this header.
     /// </remarks>
     public static bool IsHtmxFullRequest(this HttpRequest request) =>
+        // PERF: Compare the header directly instead of using GetHtmxHeaders().RequestType.
+        // The parser also recognizes "partial", and the JIT does not reliably eliminate
+        // that extra comparison even when the parser is inlined.
         request.Headers.TryGetValue(HtmxRequestHeaderNames.RequestType, out var value) && value is ["full"];
 
     /// <summary>
@@ -73,6 +76,7 @@ public static bool IsHtmxFullRequest(this HttpRequest request) =>
     /// including HTMX 1.x and 2.x requests without this header.
     /// </remarks>
     public static bool IsHtmxPartialRequest(this HttpRequest request) =>
+        // PERF: See IsHtmxFullRequest.
         request.Headers.TryGetValue(HtmxRequestHeaderNames.RequestType, out var value) && value is ["partial"];
 
     /// <summary>