diff --git a/phpBB/adm/style/acp_permission_roles.html b/phpBB/adm/style/acp_permission_roles.html
index 6cbbcde8d2..0eca7e9273 100644
--- a/phpBB/adm/style/acp_permission_roles.html
+++ b/phpBB/adm/style/acp_permission_roles.html
@@ -96,7 +96,7 @@
 	<h1>{L_ACL_TYPE}</h1>
 
 	<fieldset class="quick">
-		<a href="javascript: mark_options('a_options', 'y');">{L_ALL_YES}</a> &bull; <a href="javascript: mark_options('a_options', 'n');">{L_ALL_NO}</a> &bull; <a href="javascript: mark_options('a_options', 'u');">{L_ALL_UNSET}</a>
+		<a href="javascript: mark_options('a_options', 'y');">{L_ALL_YES}</a> &bull; <a href="javascript: mark_options('a_options', 'n');">{L_ALL_NEVER}</a> &bull; <a href="javascript: mark_options('a_options', 'u');">{L_ALL_NO}</a>
 	</fieldset>
 
 	<fieldset class="permissions">
@@ -114,10 +114,10 @@
 		<!-- BEGIN auth -->
 			<!-- IF auth.S_YES -->
 				<td class="preset preset_yes">
+			<!-- ELSEIF auth.S_NEVER -->
+				<td class="preset preset_never">
 			<!-- ELSEIF auth.S_NO -->
 				<td class="preset preset_no">
-			<!-- ELSEIF auth.S_UNSET -->
-				<td class="preset preset_unset">
 			<!-- ELSE -->
 				<td class="preset preset_custom">
 			<!-- ENDIF -->
@@ -132,17 +132,17 @@
 				<tr>
 					<th scope="col" style="text-align: left; padding-left: 0;"><strong>{L_ACL_SETTING} [{auth.CAT_NAME}]</strong></th>
 					<th scope="col"><a href="javascript: mark_options('options{auth.S_ROW_COUNT}', 'y');">{L_ACL_YES}</a></th>
-					<th scope="col"><a href="javascript: mark_options('options{auth.S_ROW_COUNT}', 'u');">{L_ACL_UNSET}</a></th>
-					<th scope="col"><a href="javascript: mark_options('options{auth.S_ROW_COUNT}', 'n');">{L_ACL_NO}</a></th>
+					<th scope="col"><a href="javascript: mark_options('options{auth.S_ROW_COUNT}', 'u');">{L_ACL_NO}</a></th>
+					<th scope="col"><a href="javascript: mark_options('options{auth.S_ROW_COUNT}', 'n');">{L_ACL_NEVER}</a></th>
 				</tr>
 				</thead>
 				<tbody>
 				<!-- BEGIN mask -->
 					<!-- IF auth.mask.S_ROW_COUNT is even --><tr class="row4"><!-- ELSE --><tr class="row3"><!-- ENDIF -->
 					<th>{auth.mask.PERMISSION}</th>
-					<td class="unset"><input id="setting[{auth.mask.FIELD_NAME}]_y" name="setting[{auth.mask.FIELD_NAME}]" class="radio" type="radio"<!-- IF auth.mask.S_YES --> checked="checked"<!-- ENDIF --> value="1" /></td>
-					<td class="unset"><input id="setting[{auth.mask.FIELD_NAME}]_u" name="setting[{auth.mask.FIELD_NAME}]" class="radio" type="radio"<!-- IF auth.mask.S_UNSET --> checked="checked"<!-- ENDIF --> value="-1" /></td>
-					<td class="unset"><input id="setting[{auth.mask.FIELD_NAME}]_n" name="setting[{auth.mask.FIELD_NAME}]" class="radio" type="radio"<!-- IF auth.mask.S_NO --> checked="checked"<!-- ENDIF --> value="0" /></td>
+					<td class="no"><input id="setting[{auth.mask.FIELD_NAME}]_y" name="setting[{auth.mask.FIELD_NAME}]" class="radio" type="radio"<!-- IF auth.mask.S_YES --> checked="checked"<!-- ENDIF --> value="1" /></td>
+					<td class="no"><input id="setting[{auth.mask.FIELD_NAME}]_u" name="setting[{auth.mask.FIELD_NAME}]" class="radio" type="radio"<!-- IF auth.mask.S_NO --> checked="checked"<!-- ENDIF --> value="-1" /></td>
+					<td class="no"><input id="setting[{auth.mask.FIELD_NAME}]_n" name="setting[{auth.mask.FIELD_NAME}]" class="radio" type="radio"<!-- IF auth.mask.S_NEVER --> checked="checked"<!-- ENDIF --> value="0" /></td>
 				</tr>
 				<!-- END mask -->
 				</tbody>
diff --git a/phpBB/adm/style/admin.css b/phpBB/adm/style/admin.css
index 759a5e0749..c1bac3d3c6 100644
--- a/phpBB/adm/style/admin.css
+++ b/phpBB/adm/style/admin.css
@@ -851,12 +851,12 @@ table.pmask td.name {
 	background-color: #40C53D;
 }
 
-.permissions td.no {
+.permissions td.never {
 	width: 20px;
 	background-color: #EC7181;
 }
 
-.permissions td.unset {
+.permissions td.no {
 	width: 20px;
 	background-color: transparent;
 }
@@ -889,11 +889,11 @@ table.pmask td.name {
 	background: #DAE4EC url("../images/bg_hash2.gif") repeat;
 }
 
-.preset_no {
+.preset_never {
 	background: #ECD7DA url("../images/bg_hash3.gif") repeat;
 }
 
-.preset_unset {
+.preset_no {
 	background: #ECD7DA url("../images/bg_hash4.gif") repeat;
 }
 
diff --git a/phpBB/adm/style/permission_mask.html b/phpBB/adm/style/permission_mask.html
index b98af2dfa4..c521d7f33d 100644
--- a/phpBB/adm/style/permission_mask.html
+++ b/phpBB/adm/style/permission_mask.html
@@ -115,7 +115,7 @@
 			return;
 		}
 
-		// Mark all options to unset first...
+		// Mark all options to no (unset) first...
 		mark_options(target_id, 'u');
 
 		for (var r in settings)
@@ -179,10 +179,10 @@
 		<!-- BEGIN category -->
 			<!-- IF p_mask.f_mask.category.S_YES -->
 				<td class="preset preset_yes">
+			<!-- ELSEIF p_mask.f_mask.category.S_NEVER -->
+				<td class="preset preset_never">
 			<!-- ELSEIF p_mask.f_mask.category.S_NO -->
 				<td class="preset preset_no">
-			<!-- ELSEIF p_mask.f_mask.category.S_UNSET -->
-				<td class="preset preset_unset">
 			<!-- ELSE -->
 				<td class="preset preset_custom">
 			<!-- ENDIF -->
@@ -200,8 +200,8 @@
 				<div style="float: right; text-align: right; width: 35%;">
 					<p class="small">
 						[<a href="javascript: mark_options('a_options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}', 'y'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ALL_YES}</a>]<br />
-						[<a href="javascript: mark_options('a_options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}', 'n'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ALL_NO}</a>]<br />
-						[<a href="javascript: mark_options('a_options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}', 'u'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ALL_UNSET}</a>]
+						[<a href="javascript: mark_options('a_options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}', 'n'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ALL_NEVER}</a>]<br />
+						[<a href="javascript: mark_options('a_options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}', 'u'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ALL_NO}</a>]
 					</p>
 				</div>
 			<!-- ELSE -->
@@ -218,11 +218,11 @@
 					<th scope="col" style="text-align: left; padding-left: 0;"><strong>{L_ACL_SETTING} [{p_mask.f_mask.category.CAT_NAME}]</strong></th>
 				<!-- IF p_mask.S_VIEW -->
 					<th scope="col">{L_ACL_YES}</th>
-					<th scope="col">{L_ACL_NO}</th>
+					<th scope="col">{L_ACL_NEVER}</th>
 				<!-- ELSE -->
 					<th scope="col"><a href="javascript: mark_options('options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}{p_mask.f_mask.category.S_ROW_COUNT}', 'y'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ACL_YES}</a></th>
-					<th scope="col"><a href="javascript: mark_options('options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}{p_mask.f_mask.category.S_ROW_COUNT}', 'u'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ACL_UNSET}</a></th>
-					<th scope="col"><a href="javascript: mark_options('options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}{p_mask.f_mask.category.S_ROW_COUNT}', 'n'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ACL_NO}</a></th>
+					<th scope="col"><a href="javascript: mark_options('options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}{p_mask.f_mask.category.S_ROW_COUNT}', 'u'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ACL_NO}</a></th>
+					<th scope="col"><a href="javascript: mark_options('options{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}{p_mask.f_mask.category.S_ROW_COUNT}', 'n'); reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}');">{L_ACL_NEVER}</a></th>
 				<!-- ENDIF -->
 				</tr>
 				</thead>
@@ -231,12 +231,12 @@
 					<!-- IF p_mask.f_mask.category.mask.S_ROW_COUNT is even --><tr class="row4"><!-- ELSE --><tr class="row3"><!-- ENDIF -->
 					<th><!-- IF p_mask.f_mask.category.mask.U_TRACE --><a href="#" onclick="javascript:trace('{p_mask.f_mask.category.mask.U_TRACE}')" title="{L_TRACE_SETTING}"><img src="images/icon_trace.gif" alt="{L_TRACE_SETTING}" /></a> <!-- ENDIF -->{p_mask.f_mask.category.mask.PERMISSION}</th>
 					<!-- IF p_mask.S_VIEW -->
-						<td<!-- IF p_mask.f_mask.category.mask.S_YES --> class="yes"<!-- ELSE --> class="unset"<!-- ENDIF -->>&nbsp;</td>
-						<td<!-- IF p_mask.f_mask.category.mask.S_NO --> class="no"<!-- ELSE --> class="unset"<!-- ENDIF -->>&nbsp;</td>
+						<td<!-- IF p_mask.f_mask.category.mask.S_YES --> class="yes"<!-- ELSE --> class="no"<!-- ENDIF -->>&nbsp;</td>
+						<td<!-- IF p_mask.f_mask.category.mask.S_NEVER --> class="never"<!-- ELSE --> class="no"<!-- ENDIF -->>&nbsp;</td>
 					<!-- ELSE -->
-						<td class="unset"><input onchange="reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}')" id="{p_mask.f_mask.category.mask.S_FIELD_NAME}_y" name="{p_mask.f_mask.category.mask.S_FIELD_NAME}" class="radio" type="radio"<!-- IF p_mask.f_mask.category.mask.S_YES --> checked="checked"<!-- ENDIF --> value="1" /></td>
-						<td class="unset"><input onchange="reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}')" id="{p_mask.f_mask.category.mask.S_FIELD_NAME}_u" name="{p_mask.f_mask.category.mask.S_FIELD_NAME}" class="radio" type="radio"<!-- IF p_mask.f_mask.category.mask.S_UNSET --> checked="checked"<!-- ENDIF --> value="-1" /></td>
-						<td class="unset"><input onchange="reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}')" id="{p_mask.f_mask.category.mask.S_FIELD_NAME}_n" name="{p_mask.f_mask.category.mask.S_FIELD_NAME}" class="radio" type="radio"<!-- IF p_mask.f_mask.category.mask.S_NO --> checked="checked"<!-- ENDIF --> value="0" /></td>
+						<td class="no"><input onchange="reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}')" id="{p_mask.f_mask.category.mask.S_FIELD_NAME}_y" name="{p_mask.f_mask.category.mask.S_FIELD_NAME}" class="radio" type="radio"<!-- IF p_mask.f_mask.category.mask.S_YES --> checked="checked"<!-- ENDIF --> value="1" /></td>
+						<td class="no"><input onchange="reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}')" id="{p_mask.f_mask.category.mask.S_FIELD_NAME}_u" name="{p_mask.f_mask.category.mask.S_FIELD_NAME}" class="radio" type="radio"<!-- IF p_mask.f_mask.category.mask.S_NO --> checked="checked"<!-- ENDIF --> value="-1" /></td>
+						<td class="no"><input onchange="reset_role('role{p_mask.S_ROW_COUNT}{p_mask.f_mask.S_ROW_COUNT}')" id="{p_mask.f_mask.category.mask.S_FIELD_NAME}_n" name="{p_mask.f_mask.category.mask.S_FIELD_NAME}" class="radio" type="radio"<!-- IF p_mask.f_mask.category.mask.S_NEVER --> checked="checked"<!-- ENDIF --> value="0" /></td>
 					<!-- ENDIF -->
 				</tr>
 				<!-- END mask -->
diff --git a/phpBB/adm/style/permission_trace.html b/phpBB/adm/style/permission_trace.html
index 6b21865562..96e18c396a 100644
--- a/phpBB/adm/style/permission_trace.html
+++ b/phpBB/adm/style/permission_trace.html
@@ -22,20 +22,20 @@
 		<!-- IF trace.S_ROW_COUNT is even --><tr class="row4"><!-- ELSE --><tr class="row3"><!-- ENDIF -->
 		<td style="white-space: nowrap;"><strong>{trace.WHO}</strong></td>
 
-		<!-- IF trace.S_SETTING_NO -->
-			<td class="no">{L_ACL_NO}</td>
+		<!-- IF trace.S_SETTING_NEVER -->
+			<td class="never">{L_ACL_NEVER}</td>
 		<!-- ELSEIF trace.S_SETTING_YES -->
 			<td class="yes">{L_ACL_YES}</td>
 		<!-- ELSE -->
-			<td class="unset">{L_ACL_UNSET}</td>
+			<td class="no">{L_ACL_NO}</td>
 		<!-- ENDIF -->
 
-		<!-- IF trace.S_TOTAL_NO -->
-			<td class="no">{L_ACL_NO}</td>
+		<!-- IF trace.S_TOTAL_NEVER -->
+			<td class="never">{L_ACL_NEVER}</td>
 		<!-- ELSEIF trace.S_TOTAL_YES -->
 			<td class="yes">{L_ACL_YES}</td>
 		<!-- ELSE -->
-			<td class="unset">{L_ACL_UNSET}</td>
+			<td class="no">{L_ACL_NO}</td>
 		<!-- ENDIF -->
 
 		<td>{trace.INFORMATION}</td>
diff --git a/phpBB/develop/add_permissions.php b/phpBB/develop/add_permissions.php
index f368da5944..bc8c317c12 100644
--- a/phpBB/develop/add_permissions.php
+++ b/phpBB/develop/add_permissions.php
@@ -33,9 +33,9 @@ require($phpbb_root_path . 'includes/acm/acm_' . $acm_type . '.'.$phpEx);
 require($phpbb_root_path . 'includes/db/' . $dbms . '.'.$phpEx);
 include($phpbb_root_path . 'includes/functions.'.$phpEx);
 
-define('ACL_NO', 0);
+define('ACL_NEVER', 0);
 define('ACL_YES', 1);
-define('ACL_UNSET', -1);
+define('ACL_NO', -1);
 
 define('ACL_GROUPS_TABLE', $table_prefix.'acl_groups');
 define('ACL_OPTIONS_TABLE', $table_prefix.'acl_options');
@@ -212,14 +212,14 @@ foreach ($prefixes as $prefix)
 		
 			echo "<p><b>Adding $auth_option...</b></p>\n";
 
-			mass_auth('group', 0, 'guests', $auth_option, ACL_NO);
-			mass_auth('group', 0, 'inactive', $auth_option, ACL_NO);
-			mass_auth('group', 0, 'inactive_coppa', $auth_option, ACL_NO);
-			mass_auth('group', 0, 'registered_coppa', $auth_option, ACL_NO);
-			mass_auth('group', 0, 'registered', $auth_option, (($prefix != 'm_' && $prefix != 'a_') ? ACL_YES : ACL_NO));
-			mass_auth('group', 0, 'global_moderators', $auth_option, (($prefix != 'a_') ? ACL_YES : ACL_NO));
+			mass_auth('group', 0, 'guests', $auth_option, ACL_NEVER);
+			mass_auth('group', 0, 'inactive', $auth_option, ACL_NEVER);
+			mass_auth('group', 0, 'inactive_coppa', $auth_option, ACL_NEVER);
+			mass_auth('group', 0, 'registered_coppa', $auth_option, ACL_NEVER);
+			mass_auth('group', 0, 'registered', $auth_option, (($prefix != 'm_' && $prefix != 'a_') ? ACL_YES : ACL_NEVER));
+			mass_auth('group', 0, 'global_moderators', $auth_option, (($prefix != 'a_') ? ACL_YES : ACL_NEVER));
 			mass_auth('group', 0, 'administrators', $auth_option, ACL_YES);
-			mass_auth('group', 0, 'bots', $auth_option, (($prefix != 'm_' && $prefix != 'a_') ? ACL_YES : ACL_NO));
+			mass_auth('group', 0, 'bots', $auth_option, (($prefix != 'm_' && $prefix != 'a_') ? ACL_YES : ACL_NEVER));
 		}
 	}
 }
@@ -236,7 +236,7 @@ echo "<p><b>Done</b></p>\n";
 	$forum_id = forum ids (array|int|0) -> 0 == all forums
 	$ug_id = [int] user_id|group_id : [string] usergroup name
 	$acl_list = [string] acl entry : [array] acl entries
-	$setting = ACL_YES|ACL_NO|ACL_UNSET
+	$setting = ACL_YES|ACL_NEVER|ACL_NO
 */
 function mass_auth($ug_type, $forum_id, $ug_id, $acl_list, $setting)
 {
@@ -337,7 +337,7 @@ function mass_auth($ug_type, $forum_id, $ug_id, $acl_list, $setting)
 
 			switch ($setting)
 			{
-				case ACL_UNSET:
+				case ACL_NO:
 					if (isset($cur_auth[$forum][$auth_option_id]))
 					{
 						$sql_ary['delete'][] = "DELETE FROM $table 
diff --git a/phpBB/includes/acp/acp_permission_roles.php b/phpBB/includes/acp/acp_permission_roles.php
index 1681986a36..2026aebaf0 100644
--- a/phpBB/includes/acp/acp_permission_roles.php
+++ b/phpBB/includes/acp/acp_permission_roles.php
@@ -239,7 +239,7 @@ class acp_permission_roles
 					$auth_options = array();
 					while ($row = $db->sql_fetchrow($result))
 					{
-						$auth_options[$row['auth_option']] = ACL_UNSET;
+						$auth_options[$row['auth_option']] = ACL_NO;
 					}
 					$db->sql_freeresult($result);
 				}
@@ -294,7 +294,7 @@ class acp_permission_roles
 					)
 				);
 
-				// We need to fill the auth options array with ACL_UNSET options ;)
+				// We need to fill the auth options array with ACL_NO options ;)
 				$sql = 'SELECT auth_option_id, auth_option
 					FROM ' . ACL_OPTIONS_TABLE . "
 					WHERE auth_option LIKE '{$permission_type}%'
@@ -306,7 +306,7 @@ class acp_permission_roles
 				{
 					if (!isset($auth_options[$row['auth_option']]))
 					{
-						$auth_options[$row['auth_option']] = ACL_UNSET;
+						$auth_options[$row['auth_option']] = ACL_NO;
 					}
 				}
 				$db->sql_freeresult($result);
@@ -447,17 +447,17 @@ class acp_permission_roles
 			$template->assign_block_vars('auth', array(
 				'CAT_NAME'	=> $user->lang['permission_cat'][$cat],
 
-				'S_YES'		=> ($cat_array['S_YES'] && !$cat_array['S_NO'] && !$cat_array['S_UNSET']) ? true : false,
-				'S_NO'		=> ($cat_array['S_NO'] && !$cat_array['S_YES'] && !$cat_array['S_UNSET']) ? true : false,
-				'S_UNSET'	=> ($cat_array['S_UNSET'] && !$cat_array['S_NO'] && !$cat_array['S_YES']) ? true : false)
+				'S_YES'		=> ($cat_array['S_YES'] && !$cat_array['S_NEVER'] && !$cat_array['S_NO']) ? true : false,
+				'S_NEVER'	=> ($cat_array['S_NEVER'] && !$cat_array['S_YES'] && !$cat_array['S_NO']) ? true : false,
+				'S_NO'		=> ($cat_array['S_NO'] && !$cat_array['S_NEVER'] && !$cat_array['S_YES']) ? true : false)
 			);
 
 			foreach ($cat_array['permissions'] as $permission => $allowed)
 			{
 				$template->assign_block_vars('auth.mask', array(
 					'S_YES'		=> ($allowed == ACL_YES) ? true : false,
+					'S_NEVER'	=> ($allowed == ACL_NEVER) ? true : false,
 					'S_NO'		=> ($allowed == ACL_NO) ? true : false,
-					'S_UNSET'	=> ($allowed == ACL_UNSET) ? true : false,
 
 					'FIELD_NAME'	=> $permission,
 					'PERMISSION'	=> $user->lang['acl_' . $permission]['lang'])
@@ -484,7 +484,7 @@ class acp_permission_roles
 		$auth_settings = array();
 		while ($row = $db->sql_fetchrow($result))
 		{
-			$auth_settings[$row['auth_option']] = ACL_UNSET;
+			$auth_settings[$row['auth_option']] = ACL_NO;
 		}
 		$db->sql_freeresult($result);
 
diff --git a/phpBB/includes/acp/acp_permissions.php b/phpBB/includes/acp/acp_permissions.php
index 04766eccab..76edb094da 100644
--- a/phpBB/includes/acp/acp_permissions.php
+++ b/phpBB/includes/acp/acp_permissions.php
@@ -500,7 +500,7 @@ class acp_permissions
 				'S_SETTING_PERMISSIONS'		=> true)
 			);
 
-			$hold_ary = $auth_admin->get_mask('set', (sizeof($user_id)) ? $user_id : false, (sizeof($group_id)) ? $group_id : false, (sizeof($forum_id)) ? $forum_id : false, $permission_type, $permission_scope, ACL_UNSET);
+			$hold_ary = $auth_admin->get_mask('set', (sizeof($user_id)) ? $user_id : false, (sizeof($group_id)) ? $group_id : false, (sizeof($forum_id)) ? $forum_id : false, $permission_type, $permission_scope, ACL_NO);
 			$auth_admin->display_mask('set', $permission_type, $hold_ary, ((sizeof($user_id)) ? 'user' : 'group'), (($permission_scope == 'local') ? true : false));
 		}
 		else
@@ -509,7 +509,7 @@ class acp_permissions
 				'S_VIEWING_PERMISSIONS'		=> true)
 			);
 
-			$hold_ary = $auth_admin->get_mask('view', (sizeof($user_id)) ? $user_id : false, (sizeof($group_id)) ? $group_id : false, (sizeof($forum_id)) ? $forum_id : false, $permission_type, $permission_scope, ACL_NO);
+			$hold_ary = $auth_admin->get_mask('view', (sizeof($user_id)) ? $user_id : false, (sizeof($group_id)) ? $group_id : false, (sizeof($forum_id)) ? $forum_id : false, $permission_type, $permission_scope, ACL_NEVER);
 			$auth_admin->display_mask('view', $permission_type, $hold_ary, ((sizeof($user_id)) ? 'user' : 'group'), (($permission_scope == 'local') ? true : false));
 		}
 	}
@@ -786,10 +786,10 @@ class acp_permissions
 		}
 		$db->sql_freeresult($result);
 
-		// We need to add any ACL_UNSET setting from auth_settings to compare correctly
+		// We need to add any ACL_NO setting from auth_settings to compare correctly
 		foreach ($auth_settings as $option => $setting)
 		{
-			if ($setting == ACL_UNSET)
+			if ($setting == ACL_NO)
 			{
 				$test_auth_settings[$option] = $setting;
 			}
@@ -963,8 +963,8 @@ class acp_permissions
 			'WHO'			=> $user->lang['DEFAULT'],
 			'INFORMATION'	=> $user->lang['TRACE_DEFAULT'],
 
-			'S_SETTING_UNSET'	=> true,
-			'S_TOTAL_UNSET'		=> true)
+			'S_SETTING_NO'		=> true,
+			'S_TOTAL_NO'		=> true)
 		);
 
 		$sql = 'SELECT DISTINCT g.group_name, g.group_id, g.group_type
@@ -979,13 +979,13 @@ class acp_permissions
 		while ($row = $db->sql_fetchrow($result))
 		{
 			$groups[$row['group_id']] = array(
-				'auth_setting'		=> ACL_UNSET,
+				'auth_setting'		=> ACL_NO,
 				'group_name'		=> ($row['group_type'] == GROUP_SPECIAL) ? $user->lang['G_' . $row['group_name']] : $row['group_name']
 			);
 		}
 		$db->sql_freeresult($result);
 
-		$total = ACL_UNSET;
+		$total = ACL_NO;
 		if (sizeof($groups))
 		{
 			// Get group auth settings
@@ -1001,18 +1001,18 @@ class acp_permissions
 			{
 				switch ($row['auth_setting'])
 				{
-					case ACL_UNSET:
-						$information = $user->lang['TRACE_GROUP_UNSET'];
+					case ACL_NO:
+						$information = $user->lang['TRACE_GROUP_NO'];
 					break;
 
 					case ACL_YES:
-						$information = ($total == ACL_YES) ? $user->lang['TRACE_GROUP_YES_TOTAL_YES'] : (($total == ACL_NO) ? $user->lang['TRACE_GROUP_YES_TOTAL_NO'] : $user->lang['TRACE_GROUP_YES_TOTAL_UNSET']);
-						$total = ($total == ACL_UNSET) ? ACL_YES : $total;
+						$information = ($total == ACL_YES) ? $user->lang['TRACE_GROUP_YES_TOTAL_YES'] : (($total == ACL_NEVER) ? $user->lang['TRACE_GROUP_YES_TOTAL_NEVER'] : $user->lang['TRACE_GROUP_YES_TOTAL_NO']);
+						$total = ($total == ACL_NO) ? ACL_YES : $total;
 					break;
 
-					case ACL_NO:
-						$information = ($total == ACL_YES) ? $user->lang['TRACE_GROUP_NO_TOTAL_YES'] : (($total == ACL_NO) ? $user->lang['TRACE_GROUP_NO_TOTAL_NO'] : $user->lang['TRACE_GROUP_NO_TOTAL_UNSET']);
-						$total = ACL_NO;
+					case ACL_NEVER:
+						$information = ($total == ACL_YES) ? $user->lang['TRACE_GROUP_NEVER_TOTAL_YES'] : (($total == ACL_NEVER) ? $user->lang['TRACE_GROUP_NEVER_TOTAL_NEVER'] : $user->lang['TRACE_GROUP_NEVER_TOTAL_NO']);
+						$total = ACL_NEVER;
 					break;
 				}
 
@@ -1020,35 +1020,35 @@ class acp_permissions
 					'WHO'			=> $row['group_name'],
 					'INFORMATION'	=> $information,
 
-					'S_SETTING_UNSET'	=> ($row['auth_setting'] == ACL_UNSET) ? true : false,
-					'S_SETTING_YES'		=> ($row['auth_setting'] == ACL_YES) ? true : false,
 					'S_SETTING_NO'		=> ($row['auth_setting'] == ACL_NO) ? true : false,
-					'S_TOTAL_UNSET'		=> ($total == ACL_UNSET) ? true : false,
+					'S_SETTING_YES'		=> ($row['auth_setting'] == ACL_YES) ? true : false,
+					'S_SETTING_NEVER'	=> ($row['auth_setting'] == ACL_NEVER) ? true : false,
+					'S_TOTAL_NO'		=> ($total == ACL_NO) ? true : false,
 					'S_TOTAL_YES'		=> ($total == ACL_YES) ? true : false,
-					'S_TOTAL_NO'		=> ($total == ACL_NO) ? true : false)
+					'S_TOTAL_NEVER'		=> ($total == ACL_NEVER) ? true : false)
 				);
 			}
 		}
 
 		// Get user specific permission...
 		$hold_ary = $auth->acl_user_raw_data($user_id, $permission, $forum_id);
-		$auth_setting = (!sizeof($hold_ary)) ? ACL_UNSET : $hold_ary[$user_id][$forum_id][$permission];
+		$auth_setting = (!sizeof($hold_ary)) ? ACL_NO : $hold_ary[$user_id][$forum_id][$permission];
 
 		switch ($auth_setting)
 		{
-			case ACL_UNSET:
-				$information = ($total == ACL_UNSET) ? $user->lang['TRACE_USER_UNSET_TOTAL_UNSET'] : $user->lang['TRACE_USER_KEPT'];
-				$total = ($total == ACL_UNSET) ? ACL_NO : $total;
+			case ACL_NO:
+				$information = ($total == ACL_NO) ? $user->lang['TRACE_USER_NO_TOTAL_NO'] : $user->lang['TRACE_USER_KEPT'];
+				$total = ($total == ACL_NO) ? ACL_NEVER : $total;
 			break;
 
 			case ACL_YES:
-				$information = ($total == ACL_YES) ? $user->lang['TRACE_USER_YES_TOTAL_YES'] : (($total == ACL_NO) ? $user->lang['TRACE_USER_YES_TOTAL_NO'] : $user->lang['TRACE_USER_YES_TOTAL_UNSET']);
-				$total = ($total == ACL_UNSET) ? ACL_YES : $total;
+				$information = ($total == ACL_YES) ? $user->lang['TRACE_USER_YES_TOTAL_YES'] : (($total == ACL_NEVER) ? $user->lang['TRACE_USER_YES_TOTAL_NEVER'] : $user->lang['TRACE_USER_YES_TOTAL_NO']);
+				$total = ($total == ACL_NO) ? ACL_YES : $total;
 			break;
 
-			case ACL_NO:
-				$information = ($total == ACL_YES) ? $user->lang['TRACE_USER_NO_TOTAL_YES'] : (($total == ACL_NO) ? $user->lang['TRACE_USER_NO_TOTAL_NO'] : $user->lang['TRACE_USER_NO_TOTAL_UNSET']);
-				$total = ACL_NO;
+			case ACL_NEVER:
+				$information = ($total == ACL_YES) ? $user->lang['TRACE_USER_NEVER_TOTAL_YES'] : (($total == ACL_NEVER) ? $user->lang['TRACE_USER_NEVER_TOTAL_NEVER'] : $user->lang['TRACE_USER_NEVER_TOTAL_NO']);
+				$total = ACL_NEVER;
 			break;
 		}
 
@@ -1056,12 +1056,12 @@ class acp_permissions
 			'WHO'			=> $userdata['username'],
 			'INFORMATION'	=> $information,
 
-			'S_SETTING_UNSET'	=> ($auth_setting == ACL_UNSET) ? true : false,
-			'S_SETTING_YES'		=> ($auth_setting == ACL_YES) ? true : false,
 			'S_SETTING_NO'		=> ($auth_setting == ACL_NO) ? true : false,
-			'S_TOTAL_UNSET'		=> false,
+			'S_SETTING_YES'		=> ($auth_setting == ACL_YES) ? true : false,
+			'S_SETTING_NEVER'	=> ($auth_setting == ACL_NEVER) ? true : false,
+			'S_TOTAL_NO'		=> false,
 			'S_TOTAL_YES'		=> ($total == ACL_YES) ? true : false,
-			'S_TOTAL_NO'		=> ($total == ACL_NO) ? true : false)
+			'S_TOTAL_NEVER'		=> ($total == ACL_NEVER) ? true : false)
 		);
 
 		// global permission might overwrite local permission
@@ -1080,24 +1080,24 @@ class acp_permissions
 
 			if ($auth_setting)
 			{
-				$information = ($total == ACL_YES) ? $user->lang['TRACE_USER_GLOBAL_YES_TOTAL_YES'] : $user->lang['TRACE_USER_GLOBAL_YES_TOTAL_NO'];
+				$information = ($total == ACL_YES) ? $user->lang['TRACE_USER_GLOBAL_YES_TOTAL_YES'] : $user->lang['TRACE_USER_GLOBAL_YES_TOTAL_NEVER'];
 				$total = ACL_YES;
 			}
 			else
 			{
-				$information = $user->lang['TRACE_USER_GLOBAL_NO_TOTAL_KEPT'];
+				$information = $user->lang['TRACE_USER_GLOBAL_NEVER_TOTAL_KEPT'];
 			}
 
 			$template->assign_block_vars('trace', array(
 				'WHO'			=> sprintf($user->lang['TRACE_GLOBAL_SETTING'], $userdata['username']),
 				'INFORMATION'	=> sprintf($information, '<a href="' . $this->u_action . "&amp;u=$user_id&amp;f=0&amp;auth=$permission&amp;back=$forum_id\">", '</a>'),
 
-				'S_SETTING_UNSET'	=> false,
+				'S_SETTING_NO'		=> false,
 				'S_SETTING_YES'		=> $auth_setting,
-				'S_SETTING_NO'		=> !$auth_setting,
-				'S_TOTAL_UNSET'		=> false,
+				'S_SETTING_NEVER'	=> !$auth_setting,
+				'S_TOTAL_NO'		=> false,
 				'S_TOTAL_YES'		=> ($total == ACL_YES) ? true : false,
-				'S_TOTAL_NO'		=> ($total == ACL_NO) ? true : false)
+				'S_TOTAL_NEVER'		=> ($total == ACL_NEVER) ? true : false)
 			);
 		}
 
@@ -1108,12 +1108,12 @@ class acp_permissions
 				'WHO'			=> $userdata['username'],
 				'INFORMATION'	=> $user->lang['TRACE_USER_FOUNDER'],
 
-				'S_SETTING_UNSET'	=> ($auth_setting == ACL_UNSET) ? true : false,
-				'S_SETTING_YES'		=> ($auth_setting == ACL_YES) ? true : false,
 				'S_SETTING_NO'		=> ($auth_setting == ACL_NO) ? true : false,
-				'S_TOTAL_UNSET'		=> false,
+				'S_SETTING_YES'		=> ($auth_setting == ACL_YES) ? true : false,
+				'S_SETTING_NEVER'	=> ($auth_setting == ACL_NEVER) ? true : false,
+				'S_TOTAL_NO'		=> false,
 				'S_TOTAL_YES'		=> true,
-				'S_TOTAL_NO'		=> false)
+				'S_TOTAL_NEVER'		=> false)
 			);
 		}
 	}
diff --git a/phpBB/includes/acp/acp_users.php b/phpBB/includes/acp/acp_users.php
index 6875d19178..dc3a32663e 100644
--- a/phpBB/includes/acp/acp_users.php
+++ b/phpBB/includes/acp/acp_users.php
@@ -1841,7 +1841,7 @@ class acp_users
 
 				while ($row = $db->sql_fetchrow($result))
 				{
-					$hold_ary = $auth_admin->get_mask('view', $user_id, false, false, $row['auth_option'], 'global', ACL_NO);
+					$hold_ary = $auth_admin->get_mask('view', $user_id, false, false, $row['auth_option'], 'global', ACL_NEVER);
 					$auth_admin->display_mask('view', $row['auth_option'], $hold_ary, 'user', false, false);
 				}
 				$db->sql_freeresult($result);
@@ -1855,7 +1855,7 @@ class acp_users
 
 				while ($row = $db->sql_fetchrow($result))
 				{
-					$hold_ary = $auth_admin->get_mask('view', $user_id, false, false, $row['auth_option'], 'local', ACL_NO);
+					$hold_ary = $auth_admin->get_mask('view', $user_id, false, false, $row['auth_option'], 'local', ACL_NEVER);
 					$auth_admin->display_mask('view', $row['auth_option'], $hold_ary, 'user', true, false);
 				}
 				$db->sql_freeresult($result);
diff --git a/phpBB/includes/acp/auth.php b/phpBB/includes/acp/auth.php
index db02e5dd97..a6ff1ddc2b 100644
--- a/phpBB/includes/acp/auth.php
+++ b/phpBB/includes/acp/auth.php
@@ -81,9 +81,9 @@ class auth_admin extends auth
 	* @param mixed $forum_id forum_ids to search for. Defining a forum id also means getting local settings
 	* @param string $auth_option the auth_option defines the permission setting to look for (a_ for example)
 	* @param local|global $scope the scope defines the permission scope. If local, a forum_id is additionally required
-	* @param ACL_NO|ACL_UNSET|ACL_YES $acl_fill defines the mode those permissions not set are getting filled with
+	* @param ACL_NEVER|ACL_NO|ACL_YES $acl_fill defines the mode those permissions not set are getting filled with
 	*/
-	function get_mask($mode, $user_id = false, $group_id = false, $forum_id = false, $auth_option = false, $scope = false, $acl_fill = ACL_NO)
+	function get_mask($mode, $user_id = false, $group_id = false, $forum_id = false, $auth_option = false, $scope = false, $acl_fill = ACL_NEVER)
 	{
 		global $db, $user;
 
@@ -828,7 +828,7 @@ class auth_admin extends auth
 		// Ok, include the any-flag if one or more auth options are set to yes...
 		foreach ($auth as $auth_option => $setting)
 		{
-			if ($setting == ACL_YES && (!isset($auth[$flag]) || $auth[$flag] == ACL_NO))
+			if ($setting == ACL_YES && (!isset($auth[$flag]) || $auth[$flag] == ACL_NEVER))
 			{
 				$auth[$flag] = ACL_YES;
 			}
@@ -858,7 +858,7 @@ class auth_admin extends auth
 				{
 					$auth_option_id = (int) $this->option_ids[$auth_option];
 
-					if ($setting != ACL_UNSET)
+					if ($setting != ACL_NO)
 					{
 						foreach ($ug_id as $id)
 						{
@@ -920,7 +920,7 @@ class auth_admin extends auth
 		// Re-set any flag...
 		foreach ($auth as $auth_option => $setting)
 		{
-			if ($setting == ACL_YES && (!isset($auth[$flag]) || $auth[$flag] == ACL_NO))
+			if ($setting == ACL_YES && (!isset($auth[$flag]) || $auth[$flag] == ACL_NEVER))
 			{
 				$auth[$flag] = ACL_YES;
 			}
@@ -931,7 +931,7 @@ class auth_admin extends auth
 		{
 			$auth_option_id = (int) $this->option_ids[$auth_option];
 
-			if ($setting != ACL_UNSET)
+			if ($setting != ACL_NO)
 			{
 				$sql_ary[] = array(
 					'role_id'			=> (int) $role_id,
@@ -941,13 +941,13 @@ class auth_admin extends auth
 			}
 		}
 
-		// If no data is there, we set the any-flag to ACL_NO...
+		// If no data is there, we set the any-flag to ACL_NEVER...
 		if (!sizeof($sql_ary))
 		{
 			$sql_ary[] = array(
 				'role_id'			=> (int) $role_id,
 				'auth_option_id'	=> $this->option_ids[$flag],
-				'auth_setting'		=> ACL_NO
+				'auth_setting'		=> ACL_NEVER
 			);
 		}
 
@@ -1016,7 +1016,7 @@ class auth_admin extends auth
 			while ($row = $db->sql_fetchrow($result))
 			{
 				$option_id_ary[] = $row['auth_option_id'];
-				$auth_id_ary[$row['auth_option']] = ACL_UNSET;
+				$auth_id_ary[$row['auth_option']] = ACL_NO;
 			}
 			$db->sql_freeresult($result);
 
@@ -1093,9 +1093,9 @@ class auth_admin extends auth
 		foreach ($category_array as $cat => $cat_array)
 		{
 			$template->assign_block_vars($tpl_cat, array(
-				'S_YES'		=> ($cat_array['S_YES'] && !$cat_array['S_NO'] && !$cat_array['S_UNSET']) ? true : false,
-				'S_NO'		=> ($cat_array['S_NO'] && !$cat_array['S_YES'] && !$cat_array['S_UNSET']) ? true : false,
-				'S_UNSET'	=> ($cat_array['S_UNSET'] && !$cat_array['S_NO'] && !$cat_array['S_YES']) ? true : false,
+				'S_YES'		=> ($cat_array['S_YES'] && !$cat_array['S_NEVER'] && !$cat_array['S_NO']) ? true : false,
+				'S_NEVER'	=> ($cat_array['S_NEVER'] && !$cat_array['S_YES'] && !$cat_array['S_NO']) ? true : false,
+				'S_NO'		=> ($cat_array['S_NO'] && !$cat_array['S_NEVER'] && !$cat_array['S_YES']) ? true : false,
 							
 				'CAT_NAME'	=> $user->lang['permission_cat'][$cat])
 			);
@@ -1104,8 +1104,8 @@ class auth_admin extends auth
 			{
 				$template->assign_block_vars($tpl_cat . '.' . $tpl_mask, array(
 					'S_YES'		=> ($allowed == ACL_YES) ? true : false,
+					'S_NEVER'	=> ($allowed == ACL_NEVER) ? true : false,
 					'S_NO'		=> ($allowed == ACL_NO) ? true : false,
-					'S_UNSET'	=> ($allowed == ACL_UNSET) ? true : false,
 
 					'UG_ID'			=> $ug_id,
 					'FORUM_ID'		=> $forum_id,
@@ -1166,15 +1166,15 @@ class auth_admin extends auth
 				{
 					$content_array[$forum_id][$cat] = array(
 						'S_YES'			=> false,
+						'S_NEVER'		=> false,
 						'S_NO'			=> false,
-						'S_UNSET'		=> false,
 						'permissions'	=> array(),
 					);
 				}
 
 				$content_array[$forum_id][$cat]['S_YES'] |= ($auth_setting == ACL_YES) ? true : false;
+				$content_array[$forum_id][$cat]['S_NEVER'] |= ($auth_setting == ACL_NEVER) ? true : false;
 				$content_array[$forum_id][$cat]['S_NO'] |= ($auth_setting == ACL_NO) ? true : false;
-				$content_array[$forum_id][$cat]['S_UNSET'] |= ($auth_setting == ACL_UNSET) ? true : false;
 
 				$content_array[$forum_id][$cat]['permissions'][$permission] = $auth_setting;
 			}
@@ -1211,7 +1211,7 @@ class auth_admin extends auth
 		{
 			if (strpos($opt, 'a_') === 0)
 			{
-				$hold_ary[0][$opt] = ACL_NO;
+				$hold_ary[0][$opt] = ACL_NEVER;
 			}
 		}
 
diff --git a/phpBB/includes/auth.php b/phpBB/includes/auth.php
index 884f58ef0a..b226f0b13b 100644
--- a/phpBB/includes/auth.php
+++ b/phpBB/includes/auth.php
@@ -378,14 +378,14 @@ class auth
 
 						// If one option is allowed, the global permission for this option has to be allowed too
 						// example: if the user has the a_ permission this means he has one or more a_* permissions
-						if ($auth_ary[$opt] == ACL_YES && (!isset($bitstring[$this->acl_options[$ary_key][$option_key]]) || $bitstring[$this->acl_options[$ary_key][$option_key]] == ACL_NO))
+						if ($auth_ary[$opt] == ACL_YES && (!isset($bitstring[$this->acl_options[$ary_key][$option_key]]) || $bitstring[$this->acl_options[$ary_key][$option_key]] == ACL_NEVER))
 						{
 							$bitstring[$this->acl_options[$ary_key][$option_key]] = ACL_YES;
 						}
 					}
 					else
 					{
-						$bitstring[$id] = ACL_NO;
+						$bitstring[$id] = ACL_NEVER;
 					}
 				}
 
@@ -489,7 +489,7 @@ class auth
 		$hold_ary = array();
 
 		// First grab user settings ... each user has only one setting for each
-		// option ... so we shouldn't need any ACL_NO checks ... he says ...
+		// option ... so we shouldn't need any ACL_NEVER checks ... he says ...
 		// Grab assigned roles...
 		$sql = $db->sql_build_query('SELECT', array(
 			'SELECT'	=> 'ao.auth_option, a.auth_role_id, r.auth_setting as role_auth_setting, a.user_id, a.forum_id, a.auth_setting',
@@ -522,7 +522,7 @@ class auth
 		}
 		$db->sql_freeresult($result);
 
-		// Now grab group settings ... ACL_NO overrides ACL_YES so act appropriatley
+		// Now grab group settings ... ACL_NEVER overrides ACL_YES so act appropriatley
 		$sql = $db->sql_build_query('SELECT', array(
 			'SELECT'	=> 'ug.user_id, ao.auth_option, a.forum_id, a.auth_setting, a.auth_role_id, r.auth_setting as role_auth_setting',
 
@@ -552,13 +552,13 @@ class auth
 
 		while ($row = $db->sql_fetchrow($result))
 		{
-			if (!isset($hold_ary[$row['user_id']][$row['forum_id']][$row['auth_option']]) || (isset($hold_ary[$row['user_id']][$row['forum_id']][$row['auth_option']]) && $hold_ary[$row['user_id']][$row['forum_id']][$row['auth_option']] != ACL_NO))
+			if (!isset($hold_ary[$row['user_id']][$row['forum_id']][$row['auth_option']]) || (isset($hold_ary[$row['user_id']][$row['forum_id']][$row['auth_option']]) && $hold_ary[$row['user_id']][$row['forum_id']][$row['auth_option']] != ACL_NEVER))
 			{
 				$setting = ($row['auth_role_id']) ? $row['role_auth_setting'] : $row['auth_setting'];
 				$hold_ary[$row['user_id']][$row['forum_id']][$row['auth_option']] = $setting;
 
-				// Check for existence of ACL_YES if an option got set to NO
-				if ($setting == ACL_NO)
+				// Check for existence of ACL_YES if an option got set to ACL_NEVER
+				if ($setting == ACL_NEVER)
 				{
 					$flag = substr($row['auth_option'], 0, strpos($row['auth_option'], '_') + 1);
 
diff --git a/phpBB/includes/constants.php b/phpBB/includes/constants.php
index 5bf505243b..c3dfcbeca7 100644
--- a/phpBB/includes/constants.php
+++ b/phpBB/includes/constants.php
@@ -31,9 +31,9 @@ define('USER_FOUNDER', 3);
 //define('USER_GUEST', 4);
 
 // ACL
-define('ACL_NO', 0);
+define('ACL_NEVER', 0);
 define('ACL_YES', 1);
-define('ACL_UNSET', -1);
+define('ACL_NO', -1);
 
 // Login error codes
 define('LOGIN_CONTINUE', 1);
diff --git a/phpBB/includes/functions_admin.php b/phpBB/includes/functions_admin.php
index b1aae21a00..6b480873c3 100644
--- a/phpBB/includes/functions_admin.php
+++ b/phpBB/includes/functions_admin.php
@@ -1884,7 +1884,7 @@ function cache_moderators()
 	// Clear table
 	$db->sql_query(((SQL_LAYER != 'sqlite') ? 'TRUNCATE TABLE ' : 'DELETE FROM ') . MODERATOR_CACHE_TABLE);
 
-	// We add moderators who have forum moderator permissions without an explicit ACL_NO setting
+	// We add moderators who have forum moderator permissions without an explicit ACL_NEVER setting
 	$hold_ary = $ug_id_ary = $sql_ary = array();
 
 	// Grab all users having moderative options...
@@ -1914,8 +1914,8 @@ function cache_moderators()
 			),
 
 			'WHERE'		=> '(o.auth_option_id = a.auth_option_id OR o.auth_option_id = r.auth_option_id)
-				AND ((a.auth_setting = ' . ACL_NO . ' AND r.auth_setting IS NULL)
-					OR r.auth_setting = ' . ACL_NO . ')
+				AND ((a.auth_setting = ' . ACL_NEVER . ' AND r.auth_setting IS NULL)
+					OR r.auth_setting = ' . ACL_NEVER . ')
 				AND a.group_id = ug.group_id
 				AND ug.user_id IN (' . implode(', ', $ug_id_ary) . ")
 				AND ug.user_pending = 0
diff --git a/phpBB/language/en/acp/permissions.php b/phpBB/language/en/acp/permissions.php
index d41fbbea58..c0d5058427 100644
--- a/phpBB/language/en/acp/permissions.php
+++ b/phpBB/language/en/acp/permissions.php
@@ -49,9 +49,9 @@ $lang = array_merge($lang, array(
 		<p>For further information on setting up and managing permissions on your phpBB3 forum, please see <a href="http://www.phpbb.com/support/documentation/3.0/quickstart/quick_permissions.html">Chapter 1.5 of our Quick Start Guide</a>.</p>
 	',
 
-	'ACL_NO'				=> 'No',
+	'ACL_NEVER'				=> 'Never',
 	'ACL_SET'				=> 'Setting Permissions',
-	'ACL_SET_EXPLAIN'		=> 'Permissions are based on a simple YES/NO system. Setting an option to NO for a user or usergroup overrides any other value assigned to it. If you do not wish to assign a value for an option for this user or group select UNSET. If values are assigned for this option elsewhere they will be used in preference, else NO is assumed. All objects marked (with the checkbox in front of them) will inherit the permission set you defined.',
+	'ACL_SET_EXPLAIN'		=> 'Permissions are based on a simple YES/NO system. Setting an option to NEVER for a user or usergroup overrides any other value assigned to it. If you do not wish to assign a value for an option for this user or group select NO. If values are assigned for this option elsewhere they will be used in preference, else NEVER is assumed. All objects marked (with the checkbox in front of them) will copy the permission set you defined.',
 	'ACL_SETTING'			=> 'Setting',
 
 	'ACL_TYPE_A_'			=> 'Administrative Permissions',
@@ -65,7 +65,7 @@ $lang = array_merge($lang, array(
 	'ACL_TYPE_LOCAL_M_'		=> 'Forum Moderator Permissions',
 	'ACL_TYPE_LOCAL_F_'		=> 'Forum Permissions',
 	
-	'ACL_UNSET'				=> 'Unset',
+	'ACL_NO'				=> 'No',
 	'ACL_VIEW'				=> 'Viewing Permissions',
 	'ACL_VIEW_EXPLAIN'		=> 'Here you can see the effective permissions the user/group is having. A red square indicates that the user/group does not have the permission, a green square indicates that the user/group does have the permission.',
 	'ACL_YES'				=> 'Yes',
@@ -92,8 +92,8 @@ $lang = array_merge($lang, array(
 	'ADD_PERMISSIONS'			=> 'Add Permissions',
 	'ADD_USERS'					=> 'Add Users',
 	'ALL_GROUPS'				=> 'Select all groups',
+	'ALL_NEVER'					=> 'All Never',
 	'ALL_NO'					=> 'All No',
-	'ALL_UNSET'					=> 'All Unset',
 	'ALL_USERS'					=> 'Select all users',
 	'ALL_YES'					=> 'All Yes',
 	'APPLY_ALL_PERMISSIONS'		=> 'Apply all Permissions',
@@ -124,7 +124,7 @@ $lang = array_merge($lang, array(
 
 	'NO_AUTH_SETTING_FOUND'		=> 'Permission settings not defined.',
 	'NO_ROLE_ASSIGNED'			=> 'No role assigned...',
-	'NO_ROLE_ASSIGNED_EXPLAIN'	=> 'Setting to this role does not change permissions on the right. If you want to unset/remove all permissions you should use the "All Unset" link.',
+	'NO_ROLE_ASSIGNED_EXPLAIN'	=> 'Setting to this role does not change permissions on the right. If you want to unset/remove all permissions you should use the "All No" link.',
 	'NO_ROLE_AVAILABLE'			=> 'No role available',
 	'NO_ROLE_NAME_SPECIFIED'	=> 'Please give the role a name.',
 	'NO_ROLE_SELECTED'			=> 'Role could not be found.',
@@ -182,30 +182,30 @@ $lang = array_merge($lang, array(
 	'SET_USERS_PERMISSIONS'			=> 'Set users permissions',
 	'SET_USERS_FORUM_PERMISSIONS'	=> 'Set users forum permissions',
 
-	'TRACE_DEFAULT'					=> 'By default every permission is UNSET. So the permission can be overwritten by other settings.',
+	'TRACE_DEFAULT'					=> 'By default every permission is NO (unset). So the permission can be overwritten by other settings.',
 	'TRACE_FOR'						=> 'Trace for',
 	'TRACE_GLOBAL_SETTING'			=> '%s (global)',
-	'TRACE_GROUP_NO_TOTAL_NO'		=> 'This group\'s permission is set to NO like the total result so the old result is kept.',
-	'TRACE_GROUP_NO_TOTAL_UNSET'	=> 'This group\'s permission is set to NO which becomes the new total value because it wasn\'t set yet.',
-	'TRACE_GROUP_NO_TOTAL_YES'		=> 'This group\'s permission is set to NO which overwrites the total YES to a NO for this user.',
-	'TRACE_GROUP_UNSET'				=> 'The permission is UNSET for this group so the old total value is kept.',
-	'TRACE_GROUP_YES_TOTAL_NO'		=> 'This group\'s permission is set to YES but the total NO cannot be overwritten.',
-	'TRACE_GROUP_YES_TOTAL_UNSET'	=> 'This group\'s permission is set to YES which becomes the new total value because it wasn\'t set yet.',
+	'TRACE_GROUP_NEVER_TOTAL_NEVER'	=> 'This group\'s permission is set to NEVER like the total result so the old result is kept.',
+	'TRACE_GROUP_NEVER_TOTAL_NO'	=> 'This group\'s permission is set to NEVER which becomes the new total value because it wasn\'t set yet (set to NO).',
+	'TRACE_GROUP_NEVER_TOTAL_YES'	=> 'This group\'s permission is set to NEVER which overwrites the total YES to a NEVER for this user.',
+	'TRACE_GROUP_NO'				=> 'The permission is NO for this group so the old total value is kept.',
+	'TRACE_GROUP_YES_TOTAL_NEVER'	=> 'This group\'s permission is set to YES but the total NEVER cannot be overwritten.',
+	'TRACE_GROUP_YES_TOTAL_NO'		=> 'This group\'s permission is set to YES which becomes the new total value because it wasn\'t set yet (set to NO).',
 	'TRACE_GROUP_YES_TOTAL_YES'		=> 'This group\'s permission is set to YES and the total permission is already set to YES, so the total result is kept.',
 	'TRACE_PERMISSION'				=> 'Trace permission - %s',
 	'TRACE_SETTING'					=> 'Trace setting',
 
-	'TRACE_USER_GLOBAL_YES_TOTAL_YES'	=> 'The forum independent user permission evaluates to YES but the total permission is already set to YES, so the the total result is kept. %sTrace global permission%s',
-	'TRACE_USER_GLOBAL_YES_TOTAL_NO'	=> 'The forum independent user permission evaluates to YES which overwrites the current local result NO. %sTrace global permission%s',
-	'TRACE_USER_GLOBAL_NO_TOTAL_KEPT'	=> 'The forum independent user permission evaluates to NO which doesn\'t influence the local permission. %sTrace global permission%s',
+	'TRACE_USER_GLOBAL_YES_TOTAL_YES'		=> 'The forum independent user permission evaluates to YES but the total permission is already set to YES, so the the total result is kept. %sTrace global permission%s',
+	'TRACE_USER_GLOBAL_YES_TOTAL_NEVER'		=> 'The forum independent user permission evaluates to YES which overwrites the current local result NEVER. %sTrace global permission%s',
+	'TRACE_USER_GLOBAL_NEVER_TOTAL_KEPT'	=> 'The forum independent user permission evaluates to NEVER which doesn\'t influence the local permission. %sTrace global permission%s',
 	'TRACE_USER_FOUNDER'			=> 'The user has the founder type set, therefore admin permissions are set to YES by default.',
-	'TRACE_USER_KEPT'				=> 'The user permission is UNSET so the old total value is kept.',
-	'TRACE_USER_NO_TOTAL_NO'		=> 'The user permission is set to NO and the total value is set to NO, so nothing is changed.',
-	'TRACE_USER_NO_TOTAL_UNSET'		=> 'The user permission is set to NO which becomes the total value because it wasn\'t set yet.',
-	'TRACE_USER_NO_TOTAL_YES'		=> 'The user permission is set to NO and overwrites the previous YES.',
-	'TRACE_USER_UNSET_TOTAL_UNSET'	=> 'The user permission is UNSET and the total value wasn\'t set yet so it defaults to NO.',
-	'TRACE_USER_YES_TOTAL_NO'		=> 'The user permission is set to YES but the total NO cannot be overwritten.',
-	'TRACE_USER_YES_TOTAL_UNSET'	=> 'The user permission is set to YES which becomes the total value because it wasn\'t set yet.',
+	'TRACE_USER_KEPT'				=> 'The user permission is NO so the old total value is kept.',
+	'TRACE_USER_NEVER_TOTAL_NEVER'	=> 'The user permission is set to NEVER and the total value is set to NEVER, so nothing is changed.',
+	'TRACE_USER_NEVER_TOTAL_NO'		=> 'The user permission is set to NEVER which becomes the total value because it was set to NO.',
+	'TRACE_USER_NEVER_TOTAL_YES'	=> 'The user permission is set to NEVER and overwrites the previous YES.',
+	'TRACE_USER_NO_TOTAL_NO'		=> 'The user permission is NO and the total value was set to NO so it defaults to NEVER.',
+	'TRACE_USER_YES_TOTAL_NEVER'	=> 'The user permission is set to YES but the total NEVER cannot be overwritten.',
+	'TRACE_USER_YES_TOTAL_NO'		=> 'The user permission is set to YES which becomes the total value because it was set to NO.',
 	'TRACE_USER_YES_TOTAL_YES'		=> 'The user permission is set to YES and the total value is set to YES, so nothing is changed.',
 	'TRACE_WHO'						=> 'Who',
 	'TRACE_TOTAL'					=> 'Total',
diff --git a/phpBB/language/en/common.php b/phpBB/language/en/common.php
index e310e5c12d..43bb278207 100644
--- a/phpBB/language/en/common.php
+++ b/phpBB/language/en/common.php
@@ -292,6 +292,7 @@ $lang = array_merge($lang, array(
 	'NEW_POST'					=> 'New post',
 	'NEW_POSTS'					=> 'New posts',
 	'NEXT'						=> 'Next',
+	'NEVER'						=> 'Never',
 	'NO'						=> 'No',
 	'NONE'						=> 'None',
 	'NOT_AUTHORIZED'			=> 'You are not authorised to access this area.',