diff --git a/htdocs/core/class/extrafields.class.php b/htdocs/core/class/extrafields.class.php
index dde961b4fcd..2f826d906b9 100644
--- a/htdocs/core/class/extrafields.class.php
+++ b/htdocs/core/class/extrafields.class.php
@@ -1186,9 +1186,10 @@ class ExtraFields
 	 * @param  int|CommonObject     $object       			Current object or object ID. Preferably, pass the object itself.
 	 * @param  string        		$extrafieldsobjectkey	The key to use to store retrieved data (commonly $object->table_element)
 	 * @param  int	         		$mode                  	1=Used for search filters
+	 * @param  int	         		$filteronparentvalue	1=Filter the values of a dependent list on the value currently saved for its parent list. Used when the field is edited alone (the parent list is not on the form, so the javascript that filters the list can't work).
 	 * @return string
 	 */
-	public function showInputField($key, $value, $moreparam = '', $keysuffix = '', $keyprefix = '', $morecss = '', $object = 0, $extrafieldsobjectkey = '', $mode = 0)
+	public function showInputField($key, $value, $moreparam = '', $keysuffix = '', $keyprefix = '', $morecss = '', $object = 0, $extrafieldsobjectkey = '', $mode = 0, $filteronparentvalue = 0)
 	{
 		global $conf, $langs, $form, $hookmanager;
 
@@ -1471,6 +1472,19 @@ class ExtraFields
 					if (!empty($valarray[1])) {
 						$parent = $valarray[1];
 					}
+					// When the field is edited alone (not into the whole form), the parent list is not on the page, so the
+					// javascript that filters a dependent list can't do its job. In this case, we filter the values here, on
+					// the value currently saved for the parent list. Note that the selected value is always kept, whatever the
+					// parent value is, so editing the field does not silently clear it.
+					if ($filteronparentvalue && !empty($parent) && (string) $value != (string) $key2) {
+						$tmpparent = explode(':', $parent, 2);
+						if (!empty($tmpparent[1]) && is_object($object)) {
+							$parentvalue = isset($object->array_options['options_'.$tmpparent[0]]) ? $object->array_options['options_'.$tmpparent[0]] : '';
+							if ((string) $parentvalue !== '' && (string) $parentvalue !== (string) $tmpparent[1]) {
+								continue;
+							}
+						}
+					}
 					$out .= '<option value="'.$key2.'"';
 					$out .= (((string) $value == (string) $key2) ? ' selected' : '');
 					$out .= (!empty($parent) ? ' parent="'.$parent.'"' : '');
diff --git a/htdocs/core/tpl/extrafields_view.tpl.php b/htdocs/core/tpl/extrafields_view.tpl.php
index 559135e0aef..e28045ba670 100644
--- a/htdocs/core/tpl/extrafields_view.tpl.php
+++ b/htdocs/core/tpl/extrafields_view.tpl.php
@@ -311,7 +311,9 @@ if (empty($reshook) && !empty($object->table_element) && isset($extrafields->att
 				print '<input type="hidden" name="token" value="'.newToken().'">';
 				print '<input type="hidden" name="'.$fieldid.'" value="'.$object->id.'">';
 				print '<input type="hidden" name="page_y" value="">';
-				print $extrafields->showInputField($tmpkeyextra, $value, '', '', '', '', $object, $object->table_element);
+				// Last parameter is 1 because the field is edited alone: a dependent list can't be filtered by javascript
+				// here (its parent list is not on this form), so it must be filtered on the saved value of its parent.
+				print $extrafields->showInputField($tmpkeyextra, $value, '', '', '', '', $object, $object->table_element, 0, 1);
 
 				print '<input type="submit" class="button reposition" value="'.dolPrintHTMLForAttribute($langs->trans('Modify')).'">';
 
diff --git a/test/phpunit/AllTests.php b/test/phpunit/AllTests.php
index e120b9c1816..4c9cac449d5 100644
--- a/test/phpunit/AllTests.php
+++ b/test/phpunit/AllTests.php
@@ -173,6 +173,9 @@ class AllTests
 		require_once dirname(__FILE__).'/CommonObjectTest.php';
 		$suite->addTestSuite('CommonObjectTest');
 
+		require_once dirname(__FILE__).'/ExtraFieldsTest.php';
+		$suite->addTestSuite('ExtraFieldsTest');
+
 		require_once dirname(__FILE__).'/ActionCommTest.php';
 		$suite->addTestSuite('ActionCommTest');
 		require_once dirname(__FILE__).'/SocieteTest.php';
diff --git a/test/phpunit/ExtraFieldsTest.php b/test/phpunit/ExtraFieldsTest.php
new file mode 100644
index 00000000000..32e3d2c5629
--- /dev/null
+++ b/test/phpunit/ExtraFieldsTest.php
@@ -0,0 +1,183 @@
+<?php
+/* Copyright (C) 2026 Jam <jambalaya.pyoncafe@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ * or see https://www.gnu.org/
+ */
+
+/**
+ *      \file       test/phpunit/ExtraFieldsTest.php
+ *      \ingroup    test
+ *      \brief      PHPUnit test
+ *      \remarks    To run this script as CLI:  phpunit filename.php
+ */
+
+global $conf,$user,$langs,$db;
+//define('TEST_DB_FORCE_TYPE','mysql');	// This is to force using mysql driver
+//require_once 'PHPUnit/Autoload.php';
+require_once dirname(__FILE__).'/../../htdocs/master.inc.php';
+require_once dirname(__FILE__).'/../../htdocs/core/class/extrafields.class.php';
+require_once dirname(__FILE__).'/../../htdocs/societe/class/societe.class.php';
+require_once dirname(__FILE__).'/CommonClassTest.class.php';
+
+if (empty($user->id)) {
+	print "Load permissions for admin user nb 1\n";
+	$user->fetch(1);
+	$user->loadRights();
+}
+$conf->global->MAIN_DISABLE_ALL_MAILS = 1;
+
+
+/**
+ * Class for PHPUnit tests
+ *
+ * @backupGlobals disabled
+ * @backupStaticAttributes enabled
+ * @remarks	backupGlobals must be disabled to have db,conf,user and lang not erased.
+ */
+class ExtraFieldsTest extends CommonClassTest
+{
+	/**
+	 * Build an ExtraFields object with a "select" list depending on another "select" list.
+	 * The child list has one value for the parent value 'a', one for the parent value 'b',
+	 * and one value with no dependency at all.
+	 *
+	 * @return	ExtraFields		Object with the definitions loaded in memory (nothing is written in database)
+	 */
+	private function getExtraFieldsWithDependentList()
+	{
+		global $db;
+
+		$extrafields = new ExtraFields($db);
+
+		$elementtype = 'societe';
+		foreach (array('parentlist', 'childlist') as $code) {
+			$extrafields->attributes[$elementtype]['type'][$code] = 'select';
+			$extrafields->attributes[$elementtype]['label'][$code] = $code;
+			$extrafields->attributes[$elementtype]['size'][$code] = '';
+			$extrafields->attributes[$elementtype]['default'][$code] = '';
+			$extrafields->attributes[$elementtype]['computed'][$code] = '';
+			$extrafields->attributes[$elementtype]['unique'][$code] = 0;
+			$extrafields->attributes[$elementtype]['required'][$code] = 0;
+			$extrafields->attributes[$elementtype]['perms'][$code] = '';
+			$extrafields->attributes[$elementtype]['langfile'][$code] = '';
+			$extrafields->attributes[$elementtype]['list'][$code] = '1';
+			$extrafields->attributes[$elementtype]['totalizable'][$code] = 0;
+			$extrafields->attributes[$elementtype]['help'][$code] = '';
+			$extrafields->attributes[$elementtype]['alwayseditable'][$code] = 0;
+		}
+
+		$extrafields->attributes[$elementtype]['param']['parentlist'] = array('options' => array('a' => 'Value A', 'b' => 'Value B'));
+		$extrafields->attributes[$elementtype]['param']['childlist'] = array('options' => array(
+			'childofa' => 'Child of A|parentlist:a',
+			'childofb' => 'Child of B|parentlist:b',
+			'nodepend' => 'No dependency',
+		));
+
+		return $extrafields;
+	}
+
+	/**
+	 * Build a thirdparty holding a value for the parent list
+	 *
+	 * @param	string		$parentvalue	Value saved for the parent list
+	 * @param	string		$childvalue		Value saved for the dependent list
+	 * @return	Societe						Object not saved in database
+	 */
+	private function getObjectWithParentValue($parentvalue, $childvalue = '')
+	{
+		global $db;
+
+		$object = new Societe($db);
+		$object->array_options['options_parentlist'] = $parentvalue;
+		$object->array_options['options_childlist'] = $childvalue;
+
+		return $object;
+	}
+
+	/**
+	 * When the whole form is shown, all the values must be output, whatever the parent value is:
+	 * the filtering is done by javascript, on the value chosen in the parent list of the same form.
+	 *
+	 * @return void
+	 */
+	public function testShowInputFieldKeepsAllValuesOfADependentListByDefault()
+	{
+		$extrafields = $this->getExtraFieldsWithDependentList();
+		$object = $this->getObjectWithParentValue('a');
+
+		$out = $extrafields->showInputField('childlist', '', '', '', '', '', $object, 'societe');
+
+		print __METHOD__." out=".$out."\n";
+		$this->assertStringContainsString('value="childofa"', $out);
+		$this->assertStringContainsString('value="childofb"', $out);
+		$this->assertStringContainsString('parent="parentlist:a"', $out);
+	}
+
+	/**
+	 * When the field is edited alone, the parent list is not on the form, so the values must be
+	 * filtered on the value already saved for the parent list.
+	 *
+	 * @return void
+	 */
+	public function testShowInputFieldFiltersADependentListOnTheSavedParentValue()
+	{
+		$extrafields = $this->getExtraFieldsWithDependentList();
+		$object = $this->getObjectWithParentValue('a');
+
+		$out = $extrafields->showInputField('childlist', '', '', '', '', '', $object, 'societe', 0, 1);
+
+		print __METHOD__." out=".$out."\n";
+		$this->assertStringContainsString('value="childofa"', $out);
+		$this->assertStringNotContainsString('value="childofb"', $out);
+		// A value that does not depend on the parent list is always kept
+		$this->assertStringContainsString('value="nodepend"', $out);
+	}
+
+	/**
+	 * If nothing is saved for the parent list, we can't filter, so all the values must be kept.
+	 *
+	 * @return void
+	 */
+	public function testShowInputFieldKeepsAllValuesWhenParentValueIsEmpty()
+	{
+		$extrafields = $this->getExtraFieldsWithDependentList();
+		$object = $this->getObjectWithParentValue('');
+
+		$out = $extrafields->showInputField('childlist', '', '', '', '', '', $object, 'societe', 0, 1);
+
+		print __METHOD__." out=".$out."\n";
+		$this->assertStringContainsString('value="childofa"', $out);
+		$this->assertStringContainsString('value="childofb"', $out);
+	}
+
+	/**
+	 * The value currently saved must always be output, even when it does not match the parent value,
+	 * otherwise editing the field would silently clear it.
+	 *
+	 * @return void
+	 */
+	public function testShowInputFieldKeepsTheSelectedValueNotMatchingTheParentValue()
+	{
+		$extrafields = $this->getExtraFieldsWithDependentList();
+		$object = $this->getObjectWithParentValue('a', 'childofb');
+
+		$out = $extrafields->showInputField('childlist', 'childofb', '', '', '', '', $object, 'societe', 0, 1);
+
+		print __METHOD__." out=".$out."\n";
+		$this->assertStringContainsString('value="childofb"', $out);
+		$this->assertStringContainsString('selected', $out);
+		$this->assertStringContainsString('value="childofa"', $out);
+	}
+}