diff --git a/lang/en_utf8/tag.php b/lang/en_utf8/tag.php
index 6e3492e8b1b..1daf7472cb9 100644
--- a/lang/en_utf8/tag.php
+++ b/lang/en_utf8/tag.php
@@ -32,6 +32,8 @@ $string['select'] = 'Select';
 $string['tagdescription'] = 'Tag description';
 $string['tag'] = 'Tag';
 $string['tagtype'] = 'Tag type';
+$string['tagtype_official'] = 'Official';
+$string['tagtype_default'] = 'Default';
 $string['tags'] = 'Tags';
 $string['tagsaredisabled'] = 'Tags are disabled';
 $string['thingstaggedwith'] = '$a->count things tagged with \"$a->name\"';
diff --git a/tag/lib.php b/tag/lib.php
index e15f2061b08..f234db58d9b 100644
--- a/tag/lib.php
+++ b/tag/lib.php
@@ -121,9 +121,10 @@ function tag_exists($tag_name_or_id) {
 
     if (is_numeric($tag_name_or_id)) {
         return record_exists('tag', 'id', $tag_name_or_id);
-    }
-    elseif (is_string($tag_name_or_id)) {
-        return record_exists('tag', 'name', $tag_name_or_id);
+
+    } else {
+        // normalised tag names are always lowercase only
+        return record_exists('tag', 'name', moodle_strtolower($tag_name_or_id));
     }
 }
 
@@ -157,11 +158,12 @@ function tags_id($tag_names_csv) {
     $normalized_tag_names_csv = tag_normalize($tag_names_csv);
     $tag_names_csv_with_apos = "'" . str_replace(',', "','", $normalized_tag_names_csv ) . "'";
 
-    $tag_objects = get_records_list('tag','name', $tag_names_csv_with_apos, "" , "name, id" );
-
     $tags_ids = array();
-    foreach ($tag_objects as $tag) {
-        $tags_ids[$tag->name] = $tag->id;
+
+    if ($tag_objects = get_records_list('tag','name', $tag_names_csv_with_apos, "" , "name, id" )) {
+        foreach ($tag_objects as $tag) {
+            $tags_ids[$tag->name] = $tag->id;
+        }
     }
 
     return $tags_ids;
@@ -1545,158 +1547,4 @@ function print_tag_cloud($tagcloud, $shuffle=true, $max_size=180, $min_size=80,
 
 }
 
-function print_tag_management_list($perpage='100') {
-
-    global $CFG, $USER;
-    require_once($CFG->libdir.'/tablelib.php');
-
-    //setup table
-
-    $tablecolumns = array('id','name', 'fullname', 'count', 'flag', 'timemodified', 'rawname', 'tagtype', '');
-    $tableheaders = array(  get_string('id' , 'tag'),
-    get_string('name' , 'tag'),
-    get_string('owner','tag'),
-    get_string('count','tag'),
-    get_string('flag','tag'),
-    get_string('timemodified','tag'),
-    get_string('newname', 'tag'),
-    get_string('tagtype', 'tag'),
-    get_string('select', 'tag')
-    );
-
-    $table = new flexible_table('tag-management-list-'.$USER->id);
-
-    $baseurl = $CFG->wwwroot.'/tag/manage.php';
-
-    $table->define_columns($tablecolumns);
-    $table->define_headers($tableheaders);
-    $table->define_baseurl($baseurl);
-
-    $table->sortable(true, 'flag', SORT_DESC);
-
-    $table->set_attribute('cellspacing', '0');
-    $table->set_attribute('id', 'tag-management-list');
-    $table->set_attribute('class', 'generaltable generalbox');
-
-    $table->set_control_variables(array(
-    TABLE_VAR_SORT    => 'ssort',
-    TABLE_VAR_HIDE    => 'shide',
-    TABLE_VAR_SHOW    => 'sshow',
-    TABLE_VAR_IFIRST  => 'sifirst',
-    TABLE_VAR_ILAST   => 'silast',
-    TABLE_VAR_PAGE    => 'spage'
-    ));
-
-    $table->setup();
-
-    if ($table->get_sql_sort()) {
-        $sort = ' ORDER BY '.$table->get_sql_sort();
-    } else {
-        $sort = '';
-    }
-
-    if ($table->get_sql_where()) {
-        $where = 'WHERE '.$table->get_sql_where();
-    } else {
-        $where = '';
-    }
-
-    $query = "
-        SELECT 
-            tg.id, tg.name, tg.rawname, tg.tagtype, COUNT(ti.id) AS count, u.id AS owner, tg.flag, tg.timemodified, u.firstname, u.lastname
-        FROM 
-            {$CFG->prefix}tag_instance ti
-        RIGHT JOIN 
-            {$CFG->prefix}tag tg 
-        ON 
-            tg.id = ti.tagid
-        LEFT JOIN
-            {$CFG->prefix}user u
-        ON
-            tg.userid = u.id
-        {$where}
-        GROUP BY 
-            tg.id 
-        {$sort}
-        ";
-
-
-    $totalcount = count_records_sql("SELECT COUNT(DISTINCT(tg.id))
-                                     FROM {$CFG->prefix}tag tg LEFT JOIN {$CFG->prefix}user u ON u.id = tg.userid
-                                     $where");
-
-    $table->initialbars(true); // always initial bars
-    $table->pagesize($perpage, $totalcount);
-
-    echo '<form id="tag-management-form" method="post" action="'.$CFG->wwwroot.'/tag/manage.php">';
-
-    //retrieve tags from DB
-    if ($tagrecords = get_records_sql($query, $table->get_page_start(),  $table->get_page_size())) {
-
-        $taglist = array_values($tagrecords);
-
-        //print_tag_cloud(array_values(get_records_sql($query)), false);
-
-        //populate table with data
-        foreach ($taglist as $tag ){
-
-            $id             =   $tag->id;
-            $name           =   '<a href="'.$CFG->wwwroot.'/tag/index.php?id='.$tag->id.'">'. tag_display_name($tag) .'</a>';
-            $owner          =   '<a href="'.$CFG->wwwroot.'/user/view.php?id='.$tag->owner.'">' . fullname($tag) . '</a>';
-            $count          =   $tag->count;
-            $flag           =   $tag->flag;
-            $timemodified   =   format_time(time() - $tag->timemodified);
-            $checkbox       =   '<input type="checkbox" name="tagschecked[]" value="'.$tag->id.'" />';
-            $text           =   '<input type="text" name="newname['.$tag->id.']" />';
-
-            // get all the possible tag types from db
-            $tagtypes = array();
-            if ($ptypes = get_records_sql("SELECT DISTINCT(tagtype), id FROM {$CFG->prefix}tag")) {
-                foreach ($ptypes as $ptype) {
-                    $tagtypes[$ptype->tagtype] = $ptype->tagtype;
-                }
-            }
-            // default types
-            $tagtypes['default']='default';
-            $tagtypes['official']='official';
-
-            $tagtype        =   choose_from_menu ($tagtypes, 'tagtypes['.$tag->id.']', $tag->tagtype, '', '', '0', true);
-
-            //if the tag if flagged, highlight it
-            if ($tag->flag > 0) {
-                $id = '<span class="flagged-tag">' . $id . '</span>';
-                $name = '<span class="flagged-tag">' . $name . '</span>';
-                $owner = '<span class="flagged-tag">' . $owner . '</span>';
-                $count = '<span class="flagged-tag">' . $count . '</span>';
-                $flag = '<span class="flagged-tag">' . $flag . '</span>';
-                $timemodified = '<span class="flagged-tag">' . $timemodified . '</span>';
-                $tagtype = '<span class="flagged-tag">'. $tagtype. '</span>';
-            }
-
-            $data = array($id, $name , $owner ,$count ,$flag, $timemodified, $text, $tagtype, $checkbox);
-
-            $table->add_data($data);
-        }
-
-
-        echo '<input type="button" onclick="checkall()" value="'.get_string('selectall').'" /> ';
-        echo '<input type="button" onclick="checknone()" value="'.get_string('deselectall').'" /> ';
-        echo '<br/><br/>';
-        echo '<select id="menuformaction" name="action">
-                    <option value="" selected="selected">'. get_string('withselectedtags', 'tag') .'</option>
-                    <option value="reset">'. get_string('resetflag', 'tag') .'</option>
-                    <option value="delete">'. get_string('delete', 'tag') .'</option>
-                    <option value="changetype">'. get_string('changetype', 'tag') .'</option>
-                    <option value="changename">'. get_string('changename', 'tag') .'</option>
-                </select>';
-
-        echo '<button id="tag-management-submit" type="submit">'. get_string('ok') .'</button>';
-
-    }
-
-    $table->print_html();
-
-    echo '</form>';
-}
-
 ?>
diff --git a/tag/manage.php b/tag/manage.php
index c91a5c6f8fd..b8250775a7a 100644
--- a/tag/manage.php
+++ b/tag/manage.php
@@ -1,12 +1,21 @@
 <?php // $Id$
 
 require_once('../config.php');
+require_once($CFG->libdir.'/tablelib.php');
 require_once('lib.php');
-require_once($CFG->dirroot.'/lib/weblib.php');
+
+define('SHOW_ALL_PAGE_SIZE', 50000);
+define('DEFAULT_PAGE_SIZE', 30);
+
+$tagschecked = optional_param('tagschecked', array(), PARAM_INT);
+$newnames    = optional_param('newname', array(), PARAM_TAG);
+$tagtypes    = optional_param('tagtypes', array(), PARAM_ALPHA);
+$action      = optional_param('action', '', PARAM_ALPHA);
+$perpage     = optional_param('perpage', DEFAULT_PAGE_SIZE, PARAM_INT);
 
 require_login();
 
-if( empty($CFG->usetags)) {
+if (empty($CFG->usetags)) {
     error(get_string('tagsaredisabled', 'tag'));
 }
 
@@ -14,11 +23,6 @@ if( empty($CFG->usetags)) {
 $systemcontext   = get_context_instance(CONTEXT_SYSTEM);
 require_capability('moodle/tag:manage', $systemcontext);
 
-$tagschecked    = optional_param('tagschecked', array());
-$newnames       = optional_param('newname', array());
-$tagtypes       = optional_param('tagtypes', array());
-$action         = optional_param('action', '', PARAM_ALPHA);
-
 $navlinks = array();
 $navlinks[] = array('name' => get_string('tags', 'tag'), 'link' => "{$CFG->wwwroot}/tag/search.php", 'type' => '');
 $navlinks[] = array('name' => get_string('managetags', 'tag'), 'link' => '', 'type' => '');
@@ -26,72 +30,98 @@ $navlinks[] = array('name' => get_string('managetags', 'tag'), 'link' => '', 'ty
 $navigation = build_navigation($navlinks);
 print_header_simple(get_string('managetags', 'tag'), '', $navigation);
 
-$notice = tag_name_from_string(implode($tagschecked, ', '));
-$notice = str_replace(',', ', ', $notice);
-
 $err_notice = '';
+$notice = '';
+
+// get all the possible tag types from db
+$existing_tagtypes = array();
+if ($ptypes = get_records_sql("SELECT DISTINCT(tagtype), id FROM {$CFG->prefix}tag")) {
+    foreach ($ptypes as $ptype) {
+        $existing_tagtypes[$ptype->tagtype] = $ptype->tagtype;
+    }
+}
+$existing_tagtypes['official'] = get_string('tagtype_official', 'tag');
+$existing_tagtypes['default'] = get_string('tagtype_default', 'tag');
 
 switch($action) {
 
     case 'delete':
-
-        $notice .= ' --  ' . get_string('deleted','tag');
+        if (!data_submitted or !confirm_sesskey()) {
+            break;
+        }
+        $str_tagschecked = tag_name_from_string(implode($tagschecked, ','));
+        $str_tagschecked = str_replace(',', ', ', $str_tagschecked);
 
         tag_delete(implode($tagschecked, ','));
-        
-        break;
-        
-    case 'reset':
 
-        $notice .= ' -- ' . get_string('reset','tag');
-        
-        tag_flag_reset(implode($tagschecked, ','));
-        
+        $notice = $str_tagschecked.' --  '.get_string('deleted','tag');
         break;
+
+    case 'reset':
+        if (!data_submitted or !confirm_sesskey()) {
+            break;
+        }
+        $str_tagschecked = tag_name_from_string(implode($tagschecked, ','));
+        $str_tagschecked = str_replace(',', ', ', $str_tagschecked);
+
+        tag_flag_reset(implode($tagschecked, ','));
+
+        $notice = $str_tagschecked.' -- '.get_string('reset','tag');
+        break;
+
     case 'changetype':
-        
-        foreach ($tagschecked as $tag_id){
-            
+        if (!data_submitted or !confirm_sesskey()) {
+            break;
+        }
+
+        $changed = array();
+
+        foreach ($tagschecked as $tag_id) {
+            if (!in_array($tagtypes[$tag_id], $existing_tagtypes)) {
+                //can not add new types here!!
+                continue;
+            }
+
             // update tag type;
             $tag = tag_by_id($tag_id);
-            
-            $tag -> tagtype = $tagtypes[$tag_id];
+            $tag->tagtype = $tagtypes[$tag_id];
+
             if (update_record('tag', $tag)) {
-                $notice .= ' --  ' . get_string('typechanged','tag'); 
+                $changed[] = $tag_id;
             }
         }
-        
+
+        if ($changed) {
+            $str_changed = tag_name_from_string(implode($changed, ','));
+            $str_changed = str_replace(',', ', ', $str_changed);
+            $notice = $str_changed.' --  '.get_string('typechanged','tag');
+        }
         break;
+
     case 'changename':
-        
-        $normalized_new_names_csv = tag_normalize( str_replace(',,','',implode($newnames, ',')) );
-   
-        //tag names entered might already exist
-        $existing_tags = tags_id( $normalized_new_names_csv );
-        
-        //notice to warn that names already exist
-        foreach ($existing_tags as $name => $tag){
-            $err_notice .= $name . ', ';
+        if (!data_submitted or !confirm_sesskey()) {
+            break;
         }
-        if(!empty($err_notice)){
-            $err_notice .= '-- ' . get_string('namesalreadybeeingused','tag');
-        }
-                
-        
-        //update tag names with the names passed in $newnames
+
         $tags_names_changed = array();
-        foreach ($tagschecked as $tag_id){
-            $tags_names_changed[$tag_id] = str_replace(',','',$newnames[$tag_id]) ;
+
+        foreach ($tagschecked as $tag_id) {
+            if ($newnames[$tag_id] != '') {
+                if (tag_exists($newnames[$tag_id])) {
+                    $err_notice .= $newnames[$tag_id]. '-- ' . get_string('namesalreadybeeingused','tag').'<br />';
+                } else {
+                    $tags_names_changed[$tag_id] = $newnames[$tag_id];
+                }
+            }
         }
 
         $tags_names_updated = tag_update_name($tags_names_changed);
-        
+
         //notice to inform what tags had their names effectively updated
-        $notice = implode($tags_names_updated, ', ');
-        if(!empty($notice)){
+        if ($tags_names_updated){
+            $notice = implode($tags_names_updated, ', ');
             $notice .= ' -- ' . get_string('updated','tag');
         }
-
         break;
 }
 
@@ -104,8 +134,140 @@ if ($notice) {
     notify($notice , 'green');
 }
 
-print_tag_management_list();
+//setup table
 
+$tablecolumns = array('id','name', 'fullname', 'count', 'flag', 'timemodified', 'rawname', 'tagtype', '');
+$tableheaders = array(get_string('id' , 'tag'),
+                      get_string('name' , 'tag'),
+                      get_string('owner','tag'),
+                      get_string('count','tag'),
+                      get_string('flag','tag'),
+                      get_string('timemodified','tag'),
+                      get_string('newname', 'tag'),
+                      get_string('tagtype', 'tag'),
+                      get_string('select', 'tag'));
+
+$table = new flexible_table('tag-management-list-'.$USER->id);
+
+$baseurl = $CFG->wwwroot.'/tag/manage.php?perpage='.$perpage;
+
+$table->define_columns($tablecolumns);
+$table->define_headers($tableheaders);
+$table->define_baseurl($baseurl);
+
+$table->sortable(true, 'flag', SORT_DESC);
+
+$table->set_attribute('cellspacing', '0');
+$table->set_attribute('id', 'tag-management-list');
+$table->set_attribute('class', 'generaltable generalbox');
+
+$table->set_control_variables(array(
+TABLE_VAR_SORT    => 'ssort',
+TABLE_VAR_HIDE    => 'shide',
+TABLE_VAR_SHOW    => 'sshow',
+TABLE_VAR_IFIRST  => 'sifirst',
+TABLE_VAR_ILAST   => 'silast',
+TABLE_VAR_PAGE    => 'spage'
+));
+
+$table->setup();
+
+if ($table->get_sql_sort()) {
+    $sort = ' ORDER BY '.$table->get_sql_sort();
+} else {
+    $sort = '';
+}
+
+if ($table->get_sql_where()) {
+    $where = 'WHERE '.$table->get_sql_where();
+} else {
+    $where = '';
+}
+
+$query = "
+    SELECT tg.id, tg.name, tg.rawname, tg.tagtype, COUNT(ti.id) AS count, u.id AS owner, tg.flag, tg.timemodified, u.firstname, u.lastname
+      FROM {$CFG->prefix}tag_instance ti
+           RIGHT JOIN {$CFG->prefix}tag tg ON tg.id = ti.tagid
+           LEFT JOIN {$CFG->prefix}user u ON tg.userid = u.id
+  {$where}
+  GROUP BY tg.id
+   {$sort}";
+
+
+$totalcount = count_records_sql("SELECT COUNT(DISTINCT(tg.id))
+                                   FROM {$CFG->prefix}tag tg
+                                        LEFT JOIN {$CFG->prefix}user u ON u.id = tg.userid
+                                 $where");
+
+$table->initialbars(true); // always initial bars
+$table->pagesize($perpage, $totalcount);
+
+echo '<form id="tag-management-form" method="post" action="'.$CFG->wwwroot.'/tag/manage.php"><div>';
+
+//retrieve tags from DB
+if ($tagrecords = get_records_sql($query, $table->get_page_start(),  $table->get_page_size())) {
+
+    $taglist = array_values($tagrecords);
+
+    //print_tag_cloud(array_values(get_records_sql($query)), false);
+
+    //populate table with data
+    foreach ($taglist as $tag ){
+
+        $id             =   $tag->id;
+        $name           =   '<a href="'.$CFG->wwwroot.'/tag/index.php?id='.$tag->id.'">'. tag_display_name($tag) .'</a>';
+        $owner          =   '<a href="'.$CFG->wwwroot.'/user/view.php?id='.$tag->owner.'">' . fullname($tag) . '</a>';
+        $count          =   $tag->count;
+        $flag           =   $tag->flag;
+        $timemodified   =   format_time(time() - $tag->timemodified);
+        $checkbox       =   '<input type="checkbox" name="tagschecked[]" value="'.$tag->id.'" />';
+        $text           =   '<input type="text" name="newname['.$tag->id.']" />';
+
+        $tagtype        =   choose_from_menu($existing_tagtypes, 'tagtypes['.$tag->id.']', $tag->tagtype, '', '', '0', true);
+
+        //if the tag if flagged, highlight it
+        if ($tag->flag > 0) {
+            $id = '<span class="flagged-tag">' . $id . '</span>';
+            $name = '<span class="flagged-tag">' . $name . '</span>';
+            $owner = '<span class="flagged-tag">' . $owner . '</span>';
+            $count = '<span class="flagged-tag">' . $count . '</span>';
+            $flag = '<span class="flagged-tag">' . $flag . '</span>';
+            $timemodified = '<span class="flagged-tag">' . $timemodified . '</span>';
+            $tagtype = '<span class="flagged-tag">'. $tagtype. '</span>';
+        }
+
+        $data = array($id, $name, $owner, $count, $flag, $timemodified, $text, $tagtype, $checkbox);
+
+        $table->add_data($data);
+    }
+
+
+    echo '<input type="button" onclick="checkall()" value="'.get_string('selectall').'" /> ';
+    echo '<input type="button" onclick="checknone()" value="'.get_string('deselectall').'" /> ';
+    echo '<input type="hidden" name="sesskey" value="'.sesskey().'" /> ';
+    echo '<br/><br/>';
+    echo '<select id="menuformaction" name="action">
+                <option value="" selected="selected">'. get_string('withselectedtags', 'tag') .'</option>
+                <option value="reset">'. get_string('resetflag', 'tag') .'</option>
+                <option value="delete">'. get_string('delete', 'tag') .'</option>
+                <option value="changetype">'. get_string('changetype', 'tag') .'</option>
+                <option value="changename">'. get_string('changename', 'tag') .'</option>
+            </select>';
+
+    echo '<button id="tag-management-submit" type="submit">'. get_string('ok') .'</button>';
+
+}
+
+$table->print_html();
+
+echo '</div></form>';
+
+if ($perpage == SHOW_ALL_PAGE_SIZE) {
+    echo '<div id="showall"><a href="'.$baseurl.'&amp;perpage='.DEFAULT_PAGE_SIZE.'">'.get_string('showperpage', '', DEFAULT_PAGE_SIZE).'</a></div>';
+
+} else if ($totalcount > 0 and $perpage < $totalcount) {
+    echo '<div id="showall"><a href="'.$baseurl.'&amp;perpage='.SHOW_ALL_PAGE_SIZE.'">'.get_string('showall', '', $totalcount).'</a></div>';
+}
 
 echo '<br/>';