diff --git a/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/explainer/PluginCallbackProxy.kt b/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/explainer/PluginCallbackProxy.kt
index dd74e411f..17bb2f618 100644
--- a/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/explainer/PluginCallbackProxy.kt
+++ b/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/explainer/PluginCallbackProxy.kt
@@ -314,29 +314,29 @@ private fun convertToDescription(dataframeLike: Any): String =
         else -> throw IllegalArgumentException("Unsupported type: ${dataframeLike::class}")
     }.escapeHtmlForIFrame()
 
-internal fun String.escapeHtmlForIFrame(): String {
-    val str = this
-    return buildString {
-        for (c in str) {
-            when {
-                c.code > 127 || c == '\'' || c == '\\' -> {
-                    append("&#")
-                    append(c.code)
-                    append(';')
-                }
+internal fun String.escapeHtmlForIFrame(): String =
+    buildString {
+        for (c in this@escapeHtmlForIFrame) {
+            when (c) {
+                '<' -> append("&lt;")
+
+                '>' -> append("&gt;")
 
-                c == '"' -> append("&quot;")
+                '&' -> append("&amp;")
 
-                c == '<' -> append("&amp;lt;")
+                '"' -> append("&quot;")
 
-                c == '>' -> append("&amp;gt;")
+                '\'' -> append("&#39;")
 
-                c == '&' -> append("&amp;")
+                '\\' -> append("&#92;")
 
                 else -> {
-                    append(c)
+                    if (c.code > 127) {
+                        append("&#${c.code};")
+                    } else {
+                        append(c)
+                    }
                 }
             }
         }
     }
-}
diff --git a/docs/README.md b/docs/README.md
index 7fbaa78f6..3471d1beb 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -62,5 +62,3 @@ Code samples for the documentation website reside in [core/.../test/.../samples/
 and [tests/.../samples/api](../tests/src/test/kotlin/org/jetbrains/kotlinx/dataframe/samples/api) (for samples can depend on other I/O modules)
 and they are copied over to Markdown files in [docs/StardustDocs/topics](./StardustDocs/topics)
 by [Korro](https://github.com/devcrocod/korro).
-
-
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsMisc.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsMisc.html
index 29b762e40..32e25b555 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsMisc.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsMisc.html
@@ -226,7 +226,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.select { colsOf&amp;lt;String&amp;gt;() }</summary>
+                                <summary>df.select { colsOf&lt;String&gt;() }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 6</summary>
                                  <table class="dataframe" id="df_6"></table>
@@ -242,7 +242,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.select { colsOf&amp;lt;String?&amp;gt; { it.countDistinct() &amp;gt; 5 } }</summary>
+                                <summary>df.select { colsOf&lt;String?&gt; { it.countDistinct() &gt; 5 } }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 6</summary>
                                  <table class="dataframe" id="df_8"></table>
@@ -438,7 +438,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.select { colsAtAnyDepth().colsOf&amp;lt;String&amp;gt;() }</summary>
+                                <summary>df.select { colsAtAnyDepth().colsOf&lt;String&gt;() }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 6</summary>
                                  <table class="dataframe" id="df_32"></table>
@@ -454,7 +454,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.select { allExcept { colsOf&amp;lt;String&amp;gt;() } }</summary>
+                                <summary>df.select { allExcept { colsOf&lt;String&gt;() } }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 6</summary>
                                  <table class="dataframe" id="df_34"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsModifySet.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsModifySet.html
index 52e480ab8..51719d24a 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsModifySet.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsModifySet.html
@@ -274,7 +274,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.select { (colsOf&amp;lt;Int&amp;gt;() and age).distinct() }</summary>
+                                <summary>df.select { (colsOf&lt;Int&gt;() and age).distinct() }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_12"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsUsages.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsUsages.html
index 1b405ef82..47a3e74ce 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsUsages.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Access.columnSelectorsUsages.html
@@ -194,7 +194,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.fillNaNs { colsAtAnyDepth().colsOf&amp;lt;Double&amp;gt;() }.withZero()</summary>
+                                <summary>df.fillNaNs { colsAtAnyDepth().colsOf&lt;Double&gt;() }.withZero()</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_2"></table>
@@ -270,7 +270,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.gather { colsOf&amp;lt;Number&amp;gt;() }.into(&quot;key&quot;, &quot;value&quot;)</summary>
+                                <summary>df.gather { colsOf&lt;Number&gt;() }.into(&quot;key&quot;, &quot;value&quot;)</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_12"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Analyze.columnsFor.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Analyze.columnsFor.html
index d4307ef33..e2c2e9c37 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Analyze.columnsFor.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Analyze.columnsFor.html
@@ -178,7 +178,7 @@
 </head>
 <body>
                                 <details>
-                                <summary>df.minFor { colsOf&amp;lt;Int&amp;gt;() }</summary>
+                                <summary>df.minFor { colsOf&lt;Int&gt;() }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_0"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Analyze.countAggregation.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Analyze.countAggregation.html
index 8606bab03..8f74a8f1b 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Analyze.countAggregation.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Analyze.countAggregation.html
@@ -200,7 +200,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.pivot { city }.count { age &amp;gt; 18 }</summary>
+                                <summary>df.pivot { city }.count { age &gt; 18 }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_9"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.DataRowApi.conditions.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.DataRowApi.conditions.html
index 6ddaed2e0..43fa7239b 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.DataRowApi.conditions.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.DataRowApi.conditions.html
@@ -210,7 +210,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.update { weight }.where { index() &amp;gt; 4 &amp;&amp; city != &quot;Paris&quot; }.with { 50 }</summary>
+                                <summary>df.update { weight }.where { index() &gt; 4 &amp;&amp; city != &quot;Paris&quot; }.with { 50 }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_4"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Join.joinWithMatch.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Join.joinWithMatch.html
index 0b0c689c6..7637c598c 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Join.joinWithMatch.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Join.joinWithMatch.html
@@ -178,7 +178,7 @@
 </head>
 <body>
                                 <details>
-                                <summary>other.into(&quot;fullName&quot;).cast&amp;lt;Right&amp;gt;()</summary>
+                                <summary>other.into(&quot;fullName&quot;).cast&lt;Right&gt;()</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 3</summary>
                                  <table class="dataframe" id="df_0"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.convert.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.convert.html
index 5038a6108..4e7091b31 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.convert.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.convert.html
@@ -198,7 +198,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.convert { colsAtAnyDepth().colsOf&amp;lt;String&amp;gt;() }.with { it.toCharArray().toList() }</summary>
+                                <summary>df.convert { colsAtAnyDepth().colsOf&lt;String&gt;() }.with { it.toCharArray().toList() }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_2"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.convertTo.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.convertTo.html
index efbbbc02a..c915e7f07 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.convertTo.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.convertTo.html
@@ -178,7 +178,7 @@
 </head>
 <body>
                                 <details>
-                                <summary>df.convert { age }.to&amp;lt;Double&amp;gt;()</summary>
+                                <summary>df.convert { age }.to&lt;Double&gt;()</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_0"></table>
@@ -198,7 +198,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.convert { colsOf&amp;lt;Number&amp;gt;() }.to&amp;lt;String&amp;gt;()</summary>
+                                <summary>df.convert { colsOf&lt;Number&gt;() }.to&lt;String&gt;()</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_2"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.fillNulls.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.fillNulls.html
index 09e320d86..458a2e13c 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.fillNulls.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.fillNulls.html
@@ -178,7 +178,7 @@
 </head>
 <body>
                                 <details>
-                                <summary>df.fillNulls { colsOf&amp;lt;Int?&amp;gt;() }.with { -1 }</summary>
+                                <summary>df.fillNulls { colsOf&lt;Int?&gt;() }.with { -1 }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_0"></table>
@@ -200,7 +200,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.update { colsOf&amp;lt;Int?&amp;gt;() }.where { it == null }.with { -1 }</summary>
+                                <summary>df.update { colsOf&lt;Int?&gt;() }.where { it == null }.with { -1 }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_3"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.gatherNames.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.gatherNames.html
index 7ddf1b7f2..b1fdf69db 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.gatherNames.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.gatherNames.html
@@ -200,7 +200,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>pivoted.gather { &quot;London&quot;..&quot;Tokyo&quot; }.cast&amp;lt;Int&amp;gt;().where { it &amp;gt; 0 }.keysInto(&quot;city&quot;)</summary>
+                                <summary>pivoted.gather { &quot;London&quot;..&quot;Tokyo&quot; }.cast&lt;Int&gt;().where { it &gt; 0 }.keysInto(&quot;city&quot;)</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 6, columnsCount = 9</summary>
                                  <table class="dataframe" id="df_3"></table>
diff --git a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.update.html b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.update.html
index 711a79244..0bb71306c 100644
--- a/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.update.html
+++ b/docs/StardustDocs/resources/snippets/org.jetbrains.kotlinx.dataframe.samples.api.Modify.update.html
@@ -200,7 +200,7 @@
                                 </details>
                                 <br>
                                 <details>
-                                <summary>df.update { colsAtAnyDepth().colsOf&amp;lt;String&amp;gt;() }.with { it.uppercase() }</summary>
+                                <summary>df.update { colsAtAnyDepth().colsOf&lt;String&gt;() }.with { it.uppercase() }</summary>
                                                                 <details>
                                 <summary>Input DataFrame: rowsCount = 7, columnsCount = 5</summary>
                                  <table class="dataframe" id="df_3"></table>
diff --git a/docs/StardustDocs/topics/DataSchema-Data-Classes-Generation.md b/docs/StardustDocs/topics/DataSchema-Data-Classes-Generation.md
index f369b5fa9..d5faa6c62 100644
--- a/docs/StardustDocs/topics/DataSchema-Data-Classes-Generation.md
+++ b/docs/StardustDocs/topics/DataSchema-Data-Classes-Generation.md
@@ -164,8 +164,6 @@ val customers: List<Customer> = df.cast<Customer>().toList()
 
 <!---END-->
 
-<!---FUN notebook_test_generate_docs_6-->
-
 ## generateCode
 
 ```kotlin
@@ -202,6 +200,8 @@ the generated Kotlin code of `@DataSchema` interfaces and/or extension propertie
 
 ### Examples {id="generateCode-examples"}
 
+<!---FUN notebook_test_generate_docs_6-->
+
 ```kotlin
 df.generateCode("Customer")
 ```
diff --git a/tests/build.gradle.kts b/tests/build.gradle.kts
index 8018e9224..7229065b7 100644
--- a/tests/build.gradle.kts
+++ b/tests/build.gradle.kts
@@ -61,7 +61,7 @@ kotlin.sourceSets {
 korro {
     docs = fileTree(rootProject.rootDir) {
         // todo topics/*.md as a part of #898
-        include("docs/StardustDocs/topics/Utilities-Generation.md")
+        include("docs/StardustDocs/topics/DataSchema-Data-Classes-Generation.md")
         include("docs/StardustDocs/topics/read.md")
         include("docs/StardustDocs/topics/write.md")
         include("docs/StardustDocs/topics/rename.md")