diff --git a/phpBB/includes/functions_acp.php b/phpBB/includes/functions_acp.php
index ad5a359710..abf726581d 100644
--- a/phpBB/includes/functions_acp.php
+++ b/phpBB/includes/functions_acp.php
@@ -655,3 +655,30 @@ function validate_range($value_ary, &$error)
 		}
 	}
 }
+
+/**
+* Inserts new config display_vars into an exisiting display_vars array
+* at the given position.
+*
+* @param array $display_vars An array of existing config display vars
+* @param array $add_config_vars An array of new config display vars
+* @param array $where Where to place the new config vars,
+*              before or after an exisiting config, as an array
+*              of the form: array('after' => 'config_name') or
+*              array('before' => 'config_name').
+* @return array The array of config display vars
+*/
+function phpbb_insert_config_array($display_vars, $add_config_vars, $where)
+{
+	if (is_array($where) && array_key_exists(current($where), $display_vars))
+	{
+		$position = array_search(current($where), array_keys($display_vars)) + ((key($where) == 'before') ? 0 : 1);
+		$display_vars = array_merge(
+			array_slice($display_vars, 0, $position),
+			$add_config_vars,
+			array_slice($display_vars, $position)
+		);
+	}
+
+	return $display_vars;
+}
diff --git a/tests/functions/insert_config_array_test.php b/tests/functions/insert_config_array_test.php
new file mode 100644
index 0000000000..bfcb05862e
--- /dev/null
+++ b/tests/functions/insert_config_array_test.php
@@ -0,0 +1,142 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+class phpbb_functions_insert_config_array_test extends phpbb_test_case
+{
+	public function config_display_vars()
+	{
+		return array(
+			'legend1'		=> '',
+			'acp_config_1'	=> array(),
+			'acp_config_2'	=> array(),
+			'acp_config_3'	=> array(),
+			'acp_config_4'	=> array(),
+			'acp_config_5'	=> array(),
+		);
+	}
+
+	public function insert_config_array_data()
+	{
+		return array(
+			array( // Add a new config after 1st array item
+				array('new_config_1' => array()),
+				array('after' => 'legend1'),
+				array(
+					'legend1'		=> '',
+					'new_config_1'	=> array(),
+					'acp_config_1'	=> array(),
+					'acp_config_2'	=> array(),
+					'acp_config_3'	=> array(),
+					'acp_config_4'	=> array(),
+					'acp_config_5'	=> array(),
+				),
+			),
+			array( // Add a new config after last array item
+				array('new_config_1' => array()),
+				array('after' => 'acp_config_5'),
+				array(
+					'legend1'		=> '',
+					'acp_config_1'	=> array(),
+					'acp_config_2'	=> array(),
+					'acp_config_3'	=> array(),
+					'acp_config_4'	=> array(),
+					'acp_config_5'	=> array(),
+					'new_config_1'	=> array(),
+				),
+			),
+			array( // Add a new config before 2nd array item
+				array('new_config_1' => array()),
+				array('before' => 'acp_config_1'),
+				array(
+					'legend1'		=> '',
+					'new_config_1'	=> array(),
+					'acp_config_1'	=> array(),
+					'acp_config_2'	=> array(),
+					'acp_config_3'	=> array(),
+					'acp_config_4'	=> array(),
+					'acp_config_5'	=> array(),
+				),
+			),
+			array( // Add a new config before last config item
+				array('new_config_1' => array()),
+				array('before' => 'acp_config_5'),
+				array(
+					'legend1'		=> '',
+					'acp_config_1'	=> array(),
+					'acp_config_2'	=> array(),
+					'acp_config_3'	=> array(),
+					'acp_config_4'	=> array(),
+					'new_config_1'	=> array(),
+					'acp_config_5'	=> array(),
+				),
+			),
+			array( // When an array key does not exist
+				array('new_config_1' => array()),
+				array('after' => 'foobar'),
+				array(
+					'legend1'		=> '',
+					'acp_config_1'	=> array(),
+					'acp_config_2'	=> array(),
+					'acp_config_3'	=> array(),
+					'acp_config_4'	=> array(),
+					'acp_config_5'	=> array(),
+				),
+			),
+			array( // When after|before is not used correctly (defaults to after)
+				array('new_config_1' => array()),
+				array('foobar' => 'acp_config_1'),
+				array(
+					'legend1'		=> '',
+					'acp_config_1'	=> array(),
+					'new_config_1'	=> array(),
+					'acp_config_2'	=> array(),
+					'acp_config_3'	=> array(),
+					'acp_config_4'	=> array(),
+					'acp_config_5'	=> array(),
+				),
+			),
+			array( // Add a new config set after the last array item
+				array(
+					'legend2' => array(),
+					'new_config_1' => array(),
+					'new_config_2' => array(),
+					'new_config_3' => array(),
+				),
+				array('after' => 'acp_config_5'),
+				array(
+					'legend1'		=> '',
+					'acp_config_1'	=> array(),
+					'acp_config_2'	=> array(),
+					'acp_config_3'	=> array(),
+					'acp_config_4'	=> array(),
+					'acp_config_5'	=> array(),
+					'legend2' => array(),
+					'new_config_1' => array(),
+					'new_config_2' => array(),
+					'new_config_3' => array(),
+				),
+			),
+		);
+	}
+
+	/**
+	* @dataProvider insert_config_array_data
+	*/
+	public function test_insert_config_array($new_config, $position, $expected)
+	{
+		$config_array = $this->config_display_vars();
+		$new_config_array = phpbb_insert_config_array($config_array, $new_config, $position);
+
+		$this->assertSame($expected, $new_config_array);
+	}
+}