diff --git a/application/dashlet.class.inc.php b/application/dashlet.class.inc.php
index a298a5069..43b06b666 100644
--- a/application/dashlet.class.inc.php
+++ b/application/dashlet.class.inc.php
@@ -667,7 +667,7 @@ class DashletUnknown extends Dashlet
 	 */
 	public function GetPropertiesFields(DesignerForm $oForm)
 	{
-		$oField = new DesignerLongTextField('xml', Dict::S('UI:DashletUnknown:Prop-XMLConfiguration'), $this->sOriginalDashletXML);
+		$oField = new DesignerXMLField('xml', Dict::S('UI:DashletUnknown:Prop-XMLConfiguration'), $this->sOriginalDashletXML);
 		$oForm->AddField($oField);
 	}
 
diff --git a/application/forms.class.inc.php b/application/forms.class.inc.php
index 889efe04d..ec952e0a3 100644
--- a/application/forms.class.inc.php
+++ b/application/forms.class.inc.php
@@ -1110,13 +1110,41 @@ $('#$sId').on('change keyup validate', function() { ValidateWithPattern('$sId',
 }
 EOF
 			);
-			$sValue = "<textarea $sCSSClasses id=\"$sId\" name=\"$sName\">".utils::EscapeHtml($this->defaultValue)."</textarea>";
+			$sValue = "<textarea $sCSSClasses id=\"$sId\" name=\"$sName\">".$this->PrepareValueForRendering()."</textarea>";
 		}
 		else {
-			$sValue = "<div $sCSSClasses id=\"$sId\">".utils::EscapeHtml($this->defaultValue)."</div>";
+			$sValue = "<div $sCSSClasses id=\"$sId\">".$this->PrepareValueForRendering()."</div>";
 		}
 		return array('label' => $this->sLabel, 'value' => $sValue);
 	}
+
+	/**
+	 * @return string|null The value itself as expected for rendering. May it be encoded, escaped or else.
+	 * @since 3.1.0 N°6405
+	 */
+	protected function PrepareValueForRendering(): ?string
+	{
+		return utils::EscapeHtml($this->defaultValue);
+	}
+}
+
+/**
+ * Class DesignerXMLField
+ *
+ * Field to display XML content
+ *
+ * @author Guillaume Lajarige <guillaume.lajarige@combodo.com>
+ * @since 3.1.0 N°6405
+ */
+class DesignerXMLField extends DesignerLongTextField
+{
+	/**
+	 * @inheritDoc
+	 */
+	protected function PrepareValueForRendering(): ?string
+	{
+		return utils::EscapeHtml($this->defaultValue, true);
+	}
 }
 
 class DesignerIntegerField extends DesignerFormField
diff --git a/application/utils.inc.php b/application/utils.inc.php
index 87e4f7dc0..575da4fa1 100644
--- a/application/utils.inc.php
+++ b/application/utils.inc.php
@@ -1970,6 +1970,7 @@ SQL;
 
 	/**
 	 * @param string $sValue
+	 * @param bool $bDoubleEncode Whether to double encode the value or not
 	 *
 	 * @return string passed value with only characters having a special meaning in HTML escaped as entities
 	 *    Since 3.0.0 we were using for this {@link HtmlEntities} but it was overkill and leads to double escaping !
@@ -1977,14 +1978,15 @@ SQL;
 	 * @uses \htmlspecialchars()
 	 * @link https://www.php.net/manual/fr/function.htmlspecialchars.php
 	 * @since 3.0.0 N°3623
+	 * @since 3.1.0 N°6405 Add $bDoubleEncode parameter
 	 */
-	public static function EscapeHtml($sValue)
+	public static function EscapeHtml($sValue, bool $bDoubleEncode = false)
 	{
 		return htmlspecialchars(
 			$sValue ?? '',
 			ENT_QUOTES | ENT_DISALLOWED | ENT_HTML5,
 			WebPage::PAGES_CHARSET,
-			false
+			$bDoubleEncode
 		);
 	}
 
diff --git a/tests/php-unit-tests/unitary-tests/application/DesignerFormFieldTest.php b/tests/php-unit-tests/unitary-tests/application/DesignerFormFieldTest.php
new file mode 100644
index 000000000..eae8975eb
--- /dev/null
+++ b/tests/php-unit-tests/unitary-tests/application/DesignerFormFieldTest.php
@@ -0,0 +1,82 @@
+<?php
+/**
+ * Copyright (C) 2018 Dennis Lassiter
+ *
+ * This file is part of iTop.
+ *
+ *  iTop is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * iTop is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with iTop. If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace Combodo\iTop\Test\UnitTest\Application;
+
+use Combodo\iTop\Test\UnitTest\ItopTestCase;
+use DesignerXMLField;
+use utils;
+
+/**
+ * @covers DesignerFormField
+ */
+class DesignerFormFieldTest extends ItopTestCase
+{
+	/**
+	 * @param string $sFieldFQCN
+	 * @param string $sInputValue
+	 * @param string $sExpectedValue
+	 *
+	 * @return void
+	 * @throws \ReflectionException
+	 * @covers DesignerLongTextField::PrepareValueForRendering
+	 * @dataProvider PrepareValueForRenderingProvider
+	 */
+	public function testPrepareValueForRendering(string $sFieldFQCN, string $sInputValue, string $sExpectedValue)
+	{
+		$oField = new $sFieldFQCN('field_code', 'Field label', $sInputValue);
+
+		$sTestedValue = $this->InvokeNonPublicMethod($sFieldFQCN, 'PrepareValueForRendering', $oField, []);
+		$this->assertEquals($sExpectedValue, $sTestedValue);
+	}
+
+	public function PrepareValueForRenderingProvider(): array
+	{
+		return [
+			'DesignerLongTextField should not double encode XML' => [
+				'\\DesignerLongTextField',
+				<<<XML
+<root>
+	<title id="title">Foo &amp; Bar</title>
+</root>
+XML,
+				<<<HTML
+&lt;root&gt;
+	&lt;title id=&quot;title&quot;&gt;Foo &amp; Bar&lt;/title&gt;
+&lt;/root&gt;
+HTML
+			],
+			'DesignerXMLField should double encode XML' => [
+				'\\DesignerXMLField',
+				<<<XML
+<root>
+	<title id="title">Foo &amp; Bar</title>
+</root>
+XML,
+				<<<HTML
+&lt;root&gt;
+	&lt;title id=&quot;title&quot;&gt;Foo &amp;amp; Bar&lt;/title&gt;
+&lt;/root&gt;
+HTML
+			],
+		];
+	}
+}
diff --git a/tests/php-unit-tests/unitary-tests/application/utilsTest.php b/tests/php-unit-tests/unitary-tests/application/utilsTest.php
index fb55caeb9..4e4209c7a 100644
--- a/tests/php-unit-tests/unitary-tests/application/utilsTest.php
+++ b/tests/php-unit-tests/unitary-tests/application/utilsTest.php
@@ -841,17 +841,19 @@ class utilsTest extends ItopTestCase
 	 *
 	 * @dataProvider escapeHtmlProvider
 	 */
-	public function testEscapeHtml($sInput, $sExpectedEscaped)
+	public function testEscapeHtml($sInput, $sExpectedEscaped, $bDoubleEncode = false)
 	{
 		if (is_null($sExpectedEscaped)) {
 			$sExpectedEscaped = $sInput;
 		}
 
-		$sEscaped = utils::EscapeHtml($sInput);
+		$sEscaped = utils::EscapeHtml($sInput, $bDoubleEncode);
 		self::assertSame($sExpectedEscaped, $sEscaped);
 
 		$sEscapedDecoded = utils::EscapedHtmlDecode($sEscaped);
-		self::assertSame($sInput, $sEscapedDecoded);
+		if (false === $bDoubleEncode) {
+			self::assertSame($sInput, $sEscapedDecoded);
+		}
 	}
 
 	public function escapeHtmlProvider()
@@ -859,8 +861,17 @@ class utilsTest extends ItopTestCase
 		return [
 			'no escape' => ['abcdefghijklmnop', null],
 			'&amp;'     => ['abcdefghijklmnop&0123456789', 'abcdefghijklmnop&amp;0123456789'],
-			['"double quotes"', '&quot;double quotes&quot;'],
-			["'simple quotes'", '&apos;simple quotes&apos;'],
+			'double quotes' => ['"double quotes"', '&quot;double quotes&quot;'],
+			'simple quotes' => ["'simple quotes'", '&apos;simple quotes&apos;'],
+			'no double encode' => [
+				'<root><title>Foo & Bar</title></root>',
+				'&lt;root&gt;&lt;title&gt;Foo &amp; Bar&lt;/title&gt;&lt;/root&gt;'
+			],
+			'double encode forced (for XML mostly)' => [
+				'<root><title>Foo &amp; Bar</title></root>',
+				'&lt;root&gt;&lt;title&gt;Foo &amp;amp; Bar&lt;/title&gt;&lt;/root&gt;',
+				true
+			],
 		];
 	}
 }