18 files changed, 252 insertions, 78 deletions
diff --git a/phpBB/includes/acp/acp_attachments.php b/phpBB/includes/acp/acp_attachments.php
index 67fba1094d..4956aab241 100644
--- a/phpBB/includes/acp/acp_attachments.php
+++ b/phpBB/includes/acp/acp_attachments.php
@@ -106,7 +106,10 @@ class acp_attachments
 		{
 			case 'attach':
 
-				include_once($phpbb_root_path . 'includes/functions_posting.' . $phpEx);
+				if (!function_exists('get_supported_image_types'))
+				{
+					include($phpbb_root_path . 'includes/functions_posting.' . $phpEx);
+				}
 
 				$sql = 'SELECT group_name, cat_id
 					FROM ' . EXTENSION_GROUPS_TABLE . '
diff --git a/phpBB/includes/acp/acp_ban.php b/phpBB/includes/acp/acp_ban.php
index b555f46a94..286bc92813 100644
--- a/phpBB/includes/acp/acp_ban.php
+++ b/phpBB/includes/acp/acp_ban.php
@@ -28,7 +28,10 @@ class acp_ban
 		global $user, $template, $request, $phpbb_dispatcher;
 		global $phpbb_root_path, $phpEx;
 
-		include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		if (!function_exists('user_ban'))
+		{
+			include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		}
 
 		$bansubmit	= $request->is_set_post('bansubmit');
 		$unbansubmit = $request->is_set_post('unbansubmit');
diff --git a/phpBB/includes/acp/acp_bots.php b/phpBB/includes/acp/acp_bots.php
index 1ea320e674..2188b90729 100644
--- a/phpBB/includes/acp/acp_bots.php
+++ b/phpBB/includes/acp/acp_bots.php
@@ -141,7 +141,11 @@ class acp_bots
 
 			case 'edit':
 			case 'add':
-				include_once($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+
+				if (!function_exists('user_update_name'))
+				{
+					include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				}
 
 				$bot_row = array(
 					'bot_name'		=> utf8_normalize_nfc(request_var('bot_name', '', true)),
diff --git a/phpBB/includes/acp/acp_captcha.php b/phpBB/includes/acp/acp_captcha.php
index fa8d8fb6a9..92d5e1dda6 100644
--- a/phpBB/includes/acp/acp_captcha.php
+++ b/phpBB/includes/acp/acp_captcha.php
@@ -25,7 +25,7 @@ class acp_captcha
 
 	function main($id, $mode)
 	{
-		global $db, $user, $auth, $template;
+		global $request, $user, $auth, $template;
 		global $config, $phpbb_root_path, $phpbb_admin_path, $phpEx, $phpbb_container;
 
 		$user->add_lang('acp/board');
@@ -52,11 +52,36 @@ class acp_captcha
 		else
 		{
 			$config_vars = array(
-				'enable_confirm'		=> array('tpl' => 'REG_ENABLE', 'default' => false),
-				'enable_post_confirm'	=> array('tpl' => 'POST_ENABLE', 'default' => false),
-				'confirm_refresh'		=> array('tpl' => 'CONFIRM_REFRESH', 'default' => false),
-				'max_reg_attempts'		=> array('tpl' => 'REG_LIMIT', 'default' => 0),
-				'max_login_attempts'		=> array('tpl' => 'MAX_LOGIN_ATTEMPTS', 'default' => 0),
+				'enable_confirm'		=> array(
+					'tpl'		=> 'REG_ENABLE',
+					'default'	=> false,
+					'validate'	=> 'bool',
+					'lang'		=> 'VISUAL_CONFIRM_REG',
+				),
+				'enable_post_confirm'	=> array(
+					'tpl'		=> 'POST_ENABLE',
+					'default'	=> false,
+					'validate'	=> 'bool',
+					'lang'		=> 'VISUAL_CONFIRM_POST',
+				),
+				'confirm_refresh'		=> array(
+					'tpl'		=> 'CONFIRM_REFRESH',
+					'default'	=> false,
+					'validate'	=> 'bool',
+					'lang'		=> 'VISUAL_CONFIRM_REFRESH',
+				),
+				'max_reg_attempts'		=> array(
+					'tpl'		=> 'REG_LIMIT',
+					'default'	=> 0,
+					'validate'	=> 'int:0:99999',
+					'lang'		=> 'REG_LIMIT',
+				),
+				'max_login_attempts'	=> array(
+					'tpl'		=> 'MAX_LOGIN_ATTEMPTS',
+					'default'	=> 0,
+					'validate'	=> 'int:0:99999',
+					'lang'		=> 'MAX_LOGIN_ATTEMPTS',
+				),
 			);
 
 			$this->tpl_name = 'acp_captcha';
@@ -65,12 +90,31 @@ class acp_captcha
 			add_form_key($form_key);
 
 			$submit = request_var('main_submit', false);
+			$error = $cfg_array = array();
 
-			if ($submit && check_form_key($form_key))
+			if ($submit)
 			{
 				foreach ($config_vars as $config_var => $options)
 				{
-					set_config($config_var, request_var($config_var, $options['default']));
+					$cfg_array[$config_var] = $request->variable($config_var, $options['default']);
+				}
+				validate_config_vars($config_vars, $cfg_array, $error);
+
+				if (!check_form_key($form_key))
+				{
+					$error[] = $user->lang['FORM_INVALID'];
+				}
+				if ($error)
+				{
+					$submit = false;
+				}
+			}
+
+			if ($submit)
+			{
+				foreach ($cfg_array as $key => $value)
+				{
+					$config->set($key, $value);
 				}
 
 				if ($selected !== $config['captcha_plugin'])
@@ -94,10 +138,6 @@ class acp_captcha
 				}
 				trigger_error($user->lang['CONFIG_UPDATED'] . adm_back_link($this->u_action));
 			}
-			else if ($submit)
-			{
-				trigger_error($user->lang['FORM_INVALID'] . adm_back_link($this->u_action), E_USER_WARNING);
-			}
 			else
 			{
 				$captcha_select = '';
@@ -124,6 +164,7 @@ class acp_captcha
 					'CAPTCHA_PREVIEW_TPL'	=> $demo_captcha->get_demo_template($id),
 					'S_CAPTCHA_HAS_CONFIG'	=> $demo_captcha->has_config(),
 					'CAPTCHA_SELECT'		=> $captcha_select,
+					'ERROR_MSG'				=> implode('<br />', $error),
 
 					'U_ACTION'				=> $this->u_action,
 				));
diff --git a/phpBB/includes/acp/acp_disallow.php b/phpBB/includes/acp/acp_disallow.php
index 4c8f3cc65b..5b12013708 100644
--- a/phpBB/includes/acp/acp_disallow.php
+++ b/phpBB/includes/acp/acp_disallow.php
@@ -26,9 +26,7 @@ class acp_disallow
 	function main($id, $mode)
 	{
 		global $db, $user, $auth, $template, $cache;
-		global $config, $phpbb_root_path, $phpbb_admin_path, $phpEx;
-
-		include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		global $config, $phpbb_admin_path;
 
 		$user->add_lang('acp/posting');
 
diff --git a/phpBB/includes/acp/acp_email.php b/phpBB/includes/acp/acp_email.php
index fda9d50779..917d02318e 100644
--- a/phpBB/includes/acp/acp_email.php
+++ b/phpBB/includes/acp/acp_email.php
@@ -189,8 +189,15 @@ class acp_email
 				$db->sql_freeresult($result);
 
 				// Send the messages
-				include_once($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
-				include_once($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				if (!class_exists('messenger'))
+				{
+					include($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
+				}
+
+				if (!function_exists('get_group_name'))
+				{
+					include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				}
 				$messenger = new messenger($use_queue);
 
 				$errored = false;
diff --git a/phpBB/includes/acp/acp_groups.php b/phpBB/includes/acp/acp_groups.php
index edfada1bf1..1e0264d8e9 100644
--- a/phpBB/includes/acp/acp_groups.php
+++ b/phpBB/includes/acp/acp_groups.php
@@ -42,7 +42,10 @@ class acp_groups
 			return;
 		}
 
-		include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		if (!function_exists('group_user_attributes'))
+		{
+			include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		}
 
 		// Check and set some common vars
 		$action		= (isset($_POST['add'])) ? 'add' : ((isset($_POST['addusers'])) ? 'addusers' : request_var('action', ''));
@@ -295,7 +298,10 @@ class acp_groups
 			case 'edit':
 			case 'add':
 
-				include($phpbb_root_path . 'includes/functions_display.' . $phpEx);
+				if (!function_exists('display_forums'))
+				{
+					include($phpbb_root_path . 'includes/functions_display.' . $phpEx);
+				}
 
 				$data = $submit_ary = array();
 
@@ -666,9 +672,8 @@ class acp_groups
 						$driver = $phpbb_avatar_manager->get_driver($current_driver);
 
 						$avatars_enabled = true;
-						$config_name = $phpbb_avatar_manager->get_driver_config_name($driver);
 						$template->set_filenames(array(
-							'avatar' => "acp_avatar_options_{$config_name}.html",
+							'avatar' => $driver->get_acp_template_name(),
 						));
 
 						if ($driver->prepare_form($request, $template, $user, $avatar_data, $avatar_error))
diff --git a/phpBB/includes/acp/acp_inactive.php b/phpBB/includes/acp/acp_inactive.php
index e96c42de05..76c7a1b277 100644
--- a/phpBB/includes/acp/acp_inactive.php
+++ b/phpBB/includes/acp/acp_inactive.php
@@ -34,7 +34,10 @@ class acp_inactive
 		global $config, $db, $user, $auth, $template, $phpbb_container;
 		global $phpbb_root_path, $phpbb_admin_path, $phpEx, $table_prefix;
 
-		include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		if (!function_exists('user_active_flip'))
+		{
+			include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		}
 
 		$user->add_lang('memberlist');
 
@@ -109,7 +112,10 @@ class acp_inactive
 
 						if ($config['require_activation'] == USER_ACTIVATION_ADMIN && !empty($inactive_users))
 						{
-							include_once($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
+							if (!class_exists('messenger'))
+							{
+								include($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
+							}
 
 							$messenger = new messenger(false);
 
@@ -196,7 +202,10 @@ class acp_inactive
 					if ($row = $db->sql_fetchrow($result))
 					{
 						// Send the messages
-						include_once($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
+						if (!class_exists('messenger'))
+						{
+							include($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
+						}
 
 						$messenger = new messenger();
 						$usernames = $user_ids = array();
@@ -271,9 +280,10 @@ class acp_inactive
 
 				'REMINDED_EXPLAIN'	=> $user->lang('USER_LAST_REMINDED', (int) $row['user_reminded'], $user->format_date($row['user_reminded_time'])),
 
-				'USERNAME_FULL'		=> get_username_string('full', $row['user_id'], $row['username'], $row['user_colour'], false, append_sid("{$phpbb_admin_path}index.$phpEx", 'i=users&amp;mode=overview')),
+				'USERNAME_FULL'		=> get_username_string('full', $row['user_id'], $row['username'], $row['user_colour'], false, append_sid("{$phpbb_admin_path}index.$phpEx", 'i=users&amp;mode=overview&amp;redirect=acp_inactive')),
 				'USERNAME'			=> get_username_string('username', $row['user_id'], $row['username'], $row['user_colour']),
 				'USER_COLOR'		=> get_username_string('colour', $row['user_id'], $row['username'], $row['user_colour']),
+				'USER_EMAIL'		=> $row['user_email'],
 
 				'U_USER_ADMIN'	=> append_sid("{$phpbb_admin_path}index.$phpEx", "i=users&amp;mode=overview&amp;u={$row['user_id']}"),
 				'U_SEARCH_USER'	=> ($auth->acl_get('u_search')) ? append_sid("{$phpbb_root_path}search.$phpEx", "author_id={$row['user_id']}&amp;sr=posts") : '',
diff --git a/phpBB/includes/acp/acp_jabber.php b/phpBB/includes/acp/acp_jabber.php
index 284543acd3..a482b41e1d 100644
--- a/phpBB/includes/acp/acp_jabber.php
+++ b/phpBB/includes/acp/acp_jabber.php
@@ -34,7 +34,10 @@ class acp_jabber
 
 		$user->add_lang('acp/board');
 
-		include_once($phpbb_root_path . 'includes/functions_jabber.' . $phpEx);
+		if (!class_exists('jabber'))
+		{
+			include($phpbb_root_path . 'includes/functions_jabber.' . $phpEx);
+		}
 
 		$action	= request_var('action', '');
 		$submit = (isset($_POST['submit'])) ? true : false;
diff --git a/phpBB/includes/acp/acp_language.php b/phpBB/includes/acp/acp_language.php
index 60e338ae7c..3888a411f0 100644
--- a/phpBB/includes/acp/acp_language.php
+++ b/phpBB/includes/acp/acp_language.php
@@ -34,7 +34,10 @@ class acp_language
 		global $config, $db, $user, $template;
 		global $phpbb_root_path, $phpEx, $request;
 
-		include_once($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		if (!function_exists('validate_language_iso_name'))
+		{
+			include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		}
 
 		// Check and set some common vars
 		$action		= (isset($_POST['update_details'])) ? 'update_details' : '';
diff --git a/phpBB/includes/acp/acp_main.php b/phpBB/includes/acp/acp_main.php
index f6d728ffed..afa0f1ea61 100644
--- a/phpBB/includes/acp/acp_main.php
+++ b/phpBB/includes/acp/acp_main.php
@@ -429,20 +429,28 @@ class acp_main
 			));
 		}
 
-		$version_helper = $phpbb_container->get('version_helper');
-		try
+		if ($auth->acl_get('a_board'))
 		{
-			$recheck = $request->variable('versioncheck_force', false);
-			$updates_available = $version_helper->get_suggested_updates($recheck);
+			$version_helper = $phpbb_container->get('version_helper');
+			try
+			{
+				$recheck = $request->variable('versioncheck_force', false);
+				$updates_available = $version_helper->get_suggested_updates($recheck);
 
-			$template->assign_var('S_VERSION_UP_TO_DATE', empty($updates_available));
+				$template->assign_var('S_VERSION_UP_TO_DATE', empty($updates_available));
+			}
+			catch (\RuntimeException $e)
+			{
+				$template->assign_vars(array(
+					'S_VERSIONCHECK_FAIL'		=> true,
+					'VERSIONCHECK_FAIL_REASON'	=> ($e->getMessage() !== $user->lang('VERSIONCHECK_FAIL')) ? $e->getMessage() : '',
+				));
+			}
 		}
-		catch (\RuntimeException $e)
+		else
 		{
-			$template->assign_vars(array(
-				'S_VERSIONCHECK_FAIL'		=> true,
-				'VERSIONCHECK_FAIL_REASON'	=> ($e->getMessage() !== $user->lang('VERSIONCHECK_FAIL')) ? $e->getMessage() : '',
-			));
+			// We set this template var to true, to not display an outdated version notice.
+			$template->assign_var('S_VERSION_UP_TO_DATE', true);
 		}
 
 		/**
@@ -553,6 +561,7 @@ class acp_main
 			'U_VERSIONCHECK'	=> append_sid("{$phpbb_admin_path}index.$phpEx", 'i=update&amp;mode=version_check'),
 			'U_VERSIONCHECK_FORCE'	=> append_sid("{$phpbb_admin_path}index.$phpEx", 'versioncheck_force=1'),
 
+			'S_VERSIONCHECK'	=> ($auth->acl_get('a_board')) ? true : false,
 			'S_ACTION_OPTIONS'	=> ($auth->acl_get('a_board')) ? true : false,
 			'S_FOUNDER'			=> ($user->data['user_type'] == USER_FOUNDER) ? true : false,
 			)
diff --git a/phpBB/includes/acp/acp_permission_roles.php b/phpBB/includes/acp/acp_permission_roles.php
index cd3616208d..be4ab4676a 100644
--- a/phpBB/includes/acp/acp_permission_roles.php
+++ b/phpBB/includes/acp/acp_permission_roles.php
@@ -30,8 +30,15 @@ class acp_permission_roles
 		global $config, $phpbb_root_path, $phpbb_admin_path, $phpEx;
 		global $request;
 
-		include_once($phpbb_root_path . 'includes/functions_user.' . $phpEx);
-		include_once($phpbb_root_path . 'includes/acp/auth.' . $phpEx);
+		if (!function_exists('user_get_id_name'))
+		{
+			include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		}
+
+		if (!class_exists('auth_admin'))
+		{
+			include($phpbb_root_path . 'includes/acp/auth.' . $phpEx);
+		}
 
 		$this->auth_admin = new auth_admin();
 
diff --git a/phpBB/includes/acp/acp_permissions.php b/phpBB/includes/acp/acp_permissions.php
index cb408e304f..660afb4e93 100644
--- a/phpBB/includes/acp/acp_permissions.php
+++ b/phpBB/includes/acp/acp_permissions.php
@@ -30,8 +30,15 @@ class acp_permissions
 		global $db, $user, $auth, $template, $cache, $phpbb_container;
 		global $config, $phpbb_root_path, $phpbb_admin_path, $phpEx;
 
-		include_once($phpbb_root_path . 'includes/functions_user.' . $phpEx);
-		include_once($phpbb_root_path . 'includes/acp/auth.' . $phpEx);
+		if (!function_exists('user_get_id_name'))
+		{
+			include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		}
+
+		if (!class_exists('auth_admin'))
+		{
+			include($phpbb_root_path . 'includes/acp/auth.' . $phpEx);
+		}
 
 		$this->permissions = $phpbb_container->get('acl.permissions');
 
diff --git a/phpBB/includes/acp/acp_profile.php b/phpBB/includes/acp/acp_profile.php
index 43668b8ad5..8c7691538c 100644
--- a/phpBB/includes/acp/acp_profile.php
+++ b/phpBB/includes/acp/acp_profile.php
@@ -33,8 +33,15 @@ class acp_profile
 		global $phpbb_root_path, $phpbb_admin_path, $phpEx, $table_prefix;
 		global $request, $phpbb_container, $phpbb_dispatcher;
 
-		include($phpbb_root_path . 'includes/functions_posting.' . $phpEx);
-		include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		if (!function_exists('generate_smilies'))
+		{
+			include($phpbb_root_path . 'includes/functions_posting.' . $phpEx);
+		}
+
+		if (!function_exists('user_get_id_name'))
+		{
+			include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		}
 
 		$user->add_lang(array('ucp', 'acp/profile'));
 		$this->tpl_name = 'acp_profile';
@@ -537,13 +544,14 @@ class acp_profile
 					}
 				}
 
-				$step = (isset($_REQUEST['next'])) ? $step + 1 : ((isset($_REQUEST['prev'])) ? $step - 1 : $step);
-
 				if (sizeof($error))
 				{
-					$step--;
 					$submit = false;
 				}
+				else
+				{
+					$step = (isset($_REQUEST['next'])) ? $step + 1 : ((isset($_REQUEST['prev'])) ? $step - 1 : $step);
+				}
 
 				// Build up the specific hidden fields
 				foreach ($exclude as $num => $key_ary)
@@ -561,7 +569,7 @@ class acp_profile
 						$var = $profile_field->prepare_hidden_fields($step, $key, $action, $field_data);
 						if ($var !== null)
 						{
-							$_new_key_ary[$key] = $profile_field->prepare_hidden_fields($step, $key, $action, $field_data);
+							$_new_key_ary[$key] = $var;
 						}
 					}
 					$cp->vars = $field_data;
@@ -571,11 +579,7 @@ class acp_profile
 
 				if (!sizeof($error))
 				{
-					if ($step == 3 && (sizeof($this->lang_defs['iso']) == 1 || $save))
-					{
-						$this->save_profile_field($cp, $field_type, $action);
-					}
-					else if ($action == 'edit' && $save)
+					if (($step == 3 && (sizeof($this->lang_defs['iso']) == 1 || $save)) || ($action == 'edit' && $save))
 					{
 						$this->save_profile_field($cp, $field_type, $action);
 					}
diff --git a/phpBB/includes/acp/acp_prune.php b/phpBB/includes/acp/acp_prune.php
index e17399e3d9..98d9caabdd 100644
--- a/phpBB/includes/acp/acp_prune.php
+++ b/phpBB/includes/acp/acp_prune.php
@@ -28,7 +28,11 @@ class acp_prune
 		global $user, $phpEx, $phpbb_admin_path, $phpbb_root_path;
 
 		$user->add_lang('acp/prune');
-		include_once($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+
+		if (!function_exists('user_active_flip'))
+		{
+			include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+		}
 
 		switch ($mode)
 		{
diff --git a/phpBB/includes/acp/acp_send_statistics.php b/phpBB/includes/acp/acp_send_statistics.php
index d178be2fb0..7c9e9cf78e 100644
--- a/phpBB/includes/acp/acp_send_statistics.php
+++ b/phpBB/includes/acp/acp_send_statistics.php
@@ -27,7 +27,10 @@ class acp_send_statistics
 	{
 		global $config, $template, $phpbb_admin_path, $phpbb_root_path, $phpEx;
 
-		include($phpbb_root_path . 'includes/questionnaire/questionnaire.' . $phpEx);
+		if (!class_exists('phpbb_questionnaire_data_collector'))
+		{
+			include($phpbb_root_path . 'includes/questionnaire/questionnaire.' . $phpEx);
+		}
 
 		$collect_url = "https://www.phpbb.com/stats/receive_stats.php";
 
diff --git a/phpBB/includes/acp/acp_styles.php b/phpBB/includes/acp/acp_styles.php
index a36a6c1ecd..5181b87ecb 100644
--- a/phpBB/includes/acp/acp_styles.php
+++ b/phpBB/includes/acp/acp_styles.php
@@ -56,9 +56,12 @@ class acp_styles
 	/** @var string */
 	protected $php_ext;
 
+	/** @var \phpbb\event\dispatcher_interface */
+	protected $dispatcher;
+
 	public function main($id, $mode)
 	{
-		global $db, $user, $phpbb_admin_path, $phpbb_root_path, $phpEx, $template, $request, $cache, $auth, $config;
+		global $db, $user, $phpbb_admin_path, $phpbb_root_path, $phpEx, $template, $request, $cache, $auth, $config, $phpbb_dispatcher;
 
 		$this->db = $db;
 		$this->user = $user;
@@ -69,6 +72,7 @@ class acp_styles
 		$this->config = $config;
 		$this->phpbb_root_path = $phpbb_root_path;
 		$this->php_ext = $phpEx;
+		$this->dispatcher = $phpbb_dispatcher;
 
 		$this->default_style = $config['default_style'];
 		$this->styles_path = $this->phpbb_root_path . $this->styles_path_absolute . '/';
@@ -118,6 +122,18 @@ class acp_styles
 			)
 		);
 
+		/**
+		 * Run code before ACP styles action execution
+		 *
+		 * @event core.acp_styles_action_before
+		 * @var	int     id          Module ID
+		 * @var	string  mode        Active module
+		 * @var	string  action      Module that should be run
+		 * @since 3.1.7-RC1
+		 */
+		$vars = array('id', 'mode', 'action');
+		extract($this->dispatcher->trigger_event('core.acp_styles_action_before', compact($vars)));
+
 		// Execute actions
 		switch ($action)
 		{
diff --git a/phpBB/includes/acp/acp_users.php b/phpBB/includes/acp/acp_users.php
index 8c17fb6311..aa4470fd0e 100644
--- a/phpBB/includes/acp/acp_users.php
+++ b/phpBB/includes/acp/acp_users.php
@@ -44,6 +44,11 @@ class acp_users
 		$user_id	= request_var('u', 0);
 		$action		= request_var('action', '');
 
+		// Get referer to redirect user to the appropriate page after delete action
+		$redirect		= request_var('redirect', '');
+		$redirect_tag	= "redirect=$redirect";
+		$redirect_url	= append_sid("{$phpbb_admin_path}index.$phpEx", "i=$redirect");
+
 		$submit		= (isset($_POST['update']) && !isset($_POST['cancel'])) ? true : false;
 
 		$form_name = 'acp_users';
@@ -52,7 +57,10 @@ class acp_users
 		// Whois (special case)
 		if ($action == 'whois')
 		{
-			include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+			if (!function_exists('user_get_id_name'))
+			{
+				include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+			}
 
 			$this->page_title = 'WHOIS';
 			$this->tpl_name = 'simple_body';
@@ -146,9 +154,9 @@ class acp_users
 		}
 
 		$template->assign_vars(array(
-			'U_BACK'			=> $this->u_action,
+			'U_BACK'			=> (empty($redirect)) ? $this->u_action : $redirect_url,
 			'U_MODE_SELECT'		=> append_sid("{$phpbb_admin_path}index.$phpEx", "i=$id&amp;u=$user_id"),
-			'U_ACTION'			=> $this->u_action . '&amp;u=' . $user_id,
+			'U_ACTION'			=> $this->u_action . '&amp;u=' . $user_id . ((empty($redirect)) ? '' : '&amp;' . $redirect_tag),
 			'S_FORM_OPTIONS'	=> $s_form_options,
 			'MANAGED_USERNAME'	=> $user_row['username'])
 		);
@@ -165,7 +173,10 @@ class acp_users
 		{
 			case 'overview':
 
-				include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				if (!function_exists('user_get_id_name'))
+				{
+					include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				}
 
 				$user->add_lang('acp/ban');
 
@@ -221,19 +232,30 @@ class acp_users
 								user_delete($delete_type, $user_id, $user_row['username']);
 
 								add_log('admin', 'LOG_USER_DELETED', $user_row['username']);
-								trigger_error($user->lang['USER_DELETED'] . adm_back_link($this->u_action));
+								trigger_error($user->lang['USER_DELETED'] . adm_back_link(
+										(empty($redirect)) ? $this->u_action : $redirect_url
+									)
+								);
 							}
 							else
 							{
-								confirm_box(false, $user->lang['CONFIRM_OPERATION'], build_hidden_fields(array(
+								$delete_confirm_hidden_fields = array(
 									'u'				=> $user_id,
 									'i'				=> $id,
 									'mode'			=> $mode,
 									'action'		=> $action,
 									'update'		=> true,
 									'delete'		=> 1,
-									'delete_type'	=> $delete_type))
+									'delete_type'	=> $delete_type,
 								);
+
+								// Checks if the redirection page is specified
+								if (!empty($redirect))
+								{
+									$delete_confirm_hidden_fields['redirect'] = $redirect;
+								}
+
+								confirm_box(false, $user->lang['CONFIRM_OPERATION'], build_hidden_fields($delete_confirm_hidden_fields));
 							}
 						}
 						else
@@ -338,7 +360,10 @@ class acp_users
 
 							if ($config['email_enable'])
 							{
-								include_once($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
+								if (!class_exists('messenger'))
+								{
+									include($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
+								}
 
 								$server_url = generate_board_url();
 
@@ -421,7 +446,10 @@ class acp_users
 									$phpbb_notifications = $phpbb_container->get('notification_manager');
 									$phpbb_notifications->delete_notifications('notification.type.admin_activate_user', $user_row['user_id']);
 
-									include_once($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
+									if (!class_exists('messenger'))
+									{
+										include($phpbb_root_path . 'includes/functions_messenger.' . $phpEx);
+									}
 
 									$messenger = new messenger(false);
 
@@ -1345,7 +1373,10 @@ class acp_users
 
 			case 'profile':
 
-				include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				if (!function_exists('user_get_id_name'))
+				{
+					include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				}
 
 				$cp = $phpbb_container->get('profilefields.manager');
 
@@ -1504,7 +1535,10 @@ class acp_users
 
 			case 'prefs':
 
-				include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				if (!function_exists('user_get_id_name'))
+				{
+					include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				}
 
 				$data = array(
 					'dateformat'		=> utf8_normalize_nfc(request_var('dateformat', $user_row['user_dateformat'], true)),
@@ -1774,8 +1808,6 @@ class acp_users
 
 			case 'avatar':
 
-				include($phpbb_root_path . 'includes/functions_display.' . $phpEx);
-
 				$avatars_enabled = false;
 
 				if ($config['allow_avatar'])
@@ -1846,9 +1878,8 @@ class acp_users
 						$driver = $phpbb_avatar_manager->get_driver($current_driver);
 
 						$avatars_enabled = true;
-						$config_name = $phpbb_avatar_manager->get_driver_config_name($driver);
 						$template->set_filenames(array(
-							'avatar' => "acp_avatar_options_{$config_name}.html",
+							'avatar' => $driver->get_acp_template_name(),
 						));
 
 						if ($driver->prepare_form($request, $template, $user, $avatar_data, $error))
@@ -1930,8 +1961,15 @@ class acp_users
 
 			case 'sig':
 
-				include_once($phpbb_root_path . 'includes/functions_posting.' . $phpEx);
-				include_once($phpbb_root_path . 'includes/functions_display.' . $phpEx);
+				if (!function_exists('generate_smilies'))
+				{
+					include($phpbb_root_path . 'includes/functions_posting.' . $phpEx);
+				}
+
+				if (!function_exists('display_custom_bbcodes'))
+				{
+					include($phpbb_root_path . 'includes/functions_display.' . $phpEx);
+				}
 
 				$enable_bbcode	= ($config['allow_sig_bbcode']) ? (bool) $this->optionget($user_row, 'sig_bbcode') : false;
 				$enable_smilies	= ($config['allow_sig_smilies']) ? (bool) $this->optionget($user_row, 'sig_smilies') : false;
@@ -1942,7 +1980,10 @@ class acp_users
 
 				if ($submit || $preview)
 				{
-					include_once($phpbb_root_path . 'includes/message_parser.' . $phpEx);
+					if (!class_exists('messenger'))
+					{
+						include($phpbb_root_path . 'includes/message_parser.' . $phpEx);
+					}
 
 					$enable_bbcode	= ($config['allow_sig_bbcode']) ? ((request_var('disable_bbcode', false)) ? false : true) : false;
 					$enable_smilies	= ($config['allow_sig_smilies']) ? ((request_var('disable_smilies', false)) ? false : true) : false;
@@ -2183,7 +2224,10 @@ class acp_users
 
 			case 'groups':
 
-				include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				if (!function_exists('group_user_attributes'))
+				{
+					include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
+				}
 
 				$user->add_lang(array('groups', 'acp/groups'));
 				$group_id = request_var('g', 0);
@@ -2399,7 +2443,10 @@ class acp_users
 
 			case 'perm':
 
-				include_once($phpbb_root_path . 'includes/acp/auth.' . $phpEx);
+				if (!class_exists('auth_admin'))
+				{
+					include($phpbb_root_path . 'includes/acp/auth.' . $phpEx);
+				}
 
 				$auth_admin = new auth_admin();