diff --git a/main/calendar/agenda.inc.php b/main/calendar/agenda.inc.php
index 81bbc74237..896b35155e 100644
--- a/main/calendar/agenda.inc.php
+++ b/main/calendar/agenda.inc.php
@@ -93,7 +93,7 @@ function get_calendar_items($select_month, $select_year, $select_day = false) {
             $new_group_memberships=array();
             foreach($group_memberships as $id) {
                 // did i have access to the same
-                $has_access = GroupManager::user_has_access(api_get_user_id(),$id,GROUP_TOOL_CALENDAR);
+                $has_access = GroupManager::user_has_access(api_get_user_id(),$id,  GroupManager::GROUP_TOOL_CALENDAR);
                 $result = GroupManager::get_group_properties($id);
                 if ($has_access && $result['calendar_state']!='0' ) {
                     $new_group_memberships[]=$id;
@@ -126,7 +126,7 @@ function get_calendar_items($select_month, $select_year, $select_day = false) {
         elseif (!empty($_SESSION['group'])) {
             if (!empty($group_id)) {
                 $result = GroupManager::get_group_properties($group_id);
-                $has_access = GroupManager::user_has_access(api_get_user_id(),$group_id,GROUP_TOOL_CALENDAR);
+                $has_access = GroupManager::user_has_access(api_get_user_id(),$group_id,GroupManager::GROUP_TOOL_CALENDAR);
                 //echo '<pre>';print_R($result);
 
                 // lastedit
@@ -1434,7 +1434,7 @@ function show_user_group_filter_form() {
 	    $option = "<optgroup label=\"".get_lang("Groups")."\">";
 		foreach($group_list as $this_group) {
 			// echo "<option value=\"agenda.php?isStudentView=true&amp;group=".$this_group['id']."\">".$this_group['name']."</option>";
-			$has_access = GroupManager::user_has_access(api_get_user_id(),$this_group['id'],GROUP_TOOL_CALENDAR);
+			$has_access = GroupManager::user_has_access(api_get_user_id(),$this_group['id'], GroupManager::GROUP_TOOL_CALENDAR);
 			$result = GroupManager::get_group_properties($this_group['id']);
 
 			if ($result['calendar_state']!='0') {
diff --git a/main/forum/index.php b/main/forum/index.php
index 0349cd9a62..321167e6a1 100644
--- a/main/forum/index.php
+++ b/main/forum/index.php
@@ -281,7 +281,7 @@ if (is_array($forum_categories_list)) {
                         if ($forum['forum_of_group'] == '0') {    
                             $show_forum = true;
                         } else {
-                            $show_forum = GroupManager::user_has_access($user_id, $forum['forum_of_group'], GROUP_TOOL_FORUM); 
+                            $show_forum = GroupManager::user_has_access($user_id, $forum['forum_of_group'], GroupManager::GROUP_TOOL_FORUM); 
                         }
                     }
 
diff --git a/main/forum/newthread.php b/main/forum/newthread.php
index 813c2e3240..918147974a 100644
--- a/main/forum/newthread.php
+++ b/main/forum/newthread.php
@@ -112,7 +112,7 @@ if (!$_user['user_id'] AND $current_forum['allow_anonymous'] <> 1) {
 
 // 5. Check user access
 if ($current_forum['forum_of_group'] != 0) {
-    $show_forum = GroupManager::user_has_access(api_get_user_id(), $current_forum['forum_of_group'], GROUP_TOOL_FORUM);
+    $show_forum = GroupManager::user_has_access(api_get_user_id(), $current_forum['forum_of_group'], GroupManager::GROUP_TOOL_FORUM);
     if (!$show_forum) {
         api_not_allowed();
     }
diff --git a/main/forum/reply.php b/main/forum/reply.php
index b6141d1689..9503d49097 100644
--- a/main/forum/reply.php
+++ b/main/forum/reply.php
@@ -85,7 +85,7 @@ if (!$_user['user_id'] AND $current_forum['allow_anonymous'] == 0) {
 }
 
 if ($current_forum['forum_of_group'] != 0) {
-    $show_forum = GroupManager::user_has_access(api_get_user_id(), $current_forum['forum_of_group'], GROUP_TOOL_FORUM);
+    $show_forum = GroupManager::user_has_access(api_get_user_id(), $current_forum['forum_of_group'], GroupManager::GROUP_TOOL_FORUM);
     if (!$show_forum) {
         api_not_allowed();
     }
diff --git a/main/forum/viewforum.php b/main/forum/viewforum.php
index 48132ee7f7..1cf46db039 100644
--- a/main/forum/viewforum.php
+++ b/main/forum/viewforum.php
@@ -75,7 +75,7 @@ if (!empty($group_id)) {
     $group_properties           = GroupManager::get_group_properties($group_id);
         
     //User has access in the group?
-    $user_has_access_in_group   = GroupManager::user_has_access($userid, $group_id, GROUP_TOOL_FORUM);
+    $user_has_access_in_group   = GroupManager::user_has_access($userid, $group_id, GroupManager::GROUP_TOOL_FORUM);
     
     $is_group_tutor = GroupManager::is_tutor_of_group(api_get_user_id(), $group_id);
         
diff --git a/main/group/group.php b/main/group/group.php
index 22b56c9936..371e65a238 100644
--- a/main/group/group.php
+++ b/main/group/group.php
@@ -25,7 +25,7 @@ $current_course_tool  = TOOL_GROUP;
 // Notice for unauthorized people.
 api_protect_course_script(true);
 
-$htmlHeadXtra[] = '<script type="text/javascript">
+$htmlHeadXtra[] = '<script>
 $(document).ready( function() {
 	for (i=0;i<$(".actions").length;i++) {
 		if ($(".actions:eq("+i+")").html()=="<table border=\"0\"></table>" || $(".actions:eq("+i+")").html()=="" || $(".actions:eq("+i+")").html()==null) {
@@ -35,16 +35,12 @@ $(document).ready( function() {
  } );
  </script>';
 $nameTools = get_lang('GroupManagement');
-
-/*	Libraries */
-require_once api_get_path(LIBRARY_PATH).'groupmanager.lib.php';
-
 $course_id = api_get_course_int_id();
 
 // Create default category if it doesn't exist when group categories aren't allowed
 if (api_get_setting('allow_group_categories') == 'false') {
 	$cat_table = Database::get_course_table(TABLE_GROUP_CATEGORY);
-	$sql = "SELECT * FROM $cat_table WHERE c_id = $course_id AND id = '".DEFAULT_GROUP_CATEGORY."'";
+	$sql = "SELECT * FROM $cat_table WHERE c_id = $course_id AND id = '".GroupManager::DEFAULT_GROUP_CATEGORY."'";
 	$res = Database::query($sql);
 	$num = Database::num_rows($res);
 	if ($num == 0) {
@@ -63,6 +59,7 @@ if (!isset ($_GET['origin']) || $_GET['origin'] != 'learnpath') {
 		api_not_allowed(true);
 	}
 }
+
 Display::display_header(get_lang('Groups'));
 
 // Tool introduction
@@ -143,7 +140,7 @@ if (api_is_allowed_to_edit(false, true)) {
 				GroupManager :: unsubscribe_all_users($my_get_id);
 				Display :: display_confirmation_message(get_lang('GroupEmptied'));
 				break;
-			case 'fill_one':
+			case 'fill_one':                
 				GroupManager :: fill_groups($my_get_id);
 				Display :: display_confirmation_message(get_lang('GroupFilledGroups'));
 				break;
@@ -245,12 +242,12 @@ foreach ($group_cats as $index => $category) {
 			if ((api_is_allowed_to_edit(false, true) ||
 					in_array($_user['user_id'], $tutorsids_of_group) ||
 					$this_group['is_member'] ||
-					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GROUP_TOOL_FORUM) ||
-					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GROUP_TOOL_DOCUMENTS) ||
-					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GROUP_TOOL_CALENDAR) ||
-					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GROUP_TOOL_ANNOUNCEMENT) ||
-					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GROUP_TOOL_WORK) ||
-					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GROUP_TOOL_WIKI))
+					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GroupManager::GROUP_TOOL_FORUM) ||
+					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GroupManager::GROUP_TOOL_DOCUMENTS) ||
+					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GroupManager::GROUP_TOOL_CALENDAR) ||
+					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GroupManager::GROUP_TOOL_ANNOUNCEMENT) ||
+					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GroupManager::GROUP_TOOL_WORK) ||
+					GroupManager::user_has_access($_user['user_id'], $this_group['id'], GroupManager::GROUP_TOOL_WIKI))
 					&& !(api_is_course_coach() && intval($this_group['session_id']) != intval($_SESSION['id_session']))) {
 				$orig = isset($origin) ? $origin : null;
 				$group_name = '<a href="group_space.php?'.api_get_cidreq().'&amp;origin='.$orig.'&amp;gidReq='.$this_group['id'].'">'.stripslashes($this_group['name']).'</a>';
@@ -291,7 +288,7 @@ foreach ($group_cats as $index => $category) {
             
 		
             // Max number of members in group
-            $max_members = ($this_group['maximum_number_of_members'] == MEMBER_PER_GROUP_NO_LIMIT ? ' ' : ' / '.$this_group['maximum_number_of_members']);
+            $max_members = ($this_group['maximum_number_of_members'] == GroupManager::MEMBER_PER_GROUP_NO_LIMIT ? ' ' : ' / '.$this_group['maximum_number_of_members']);
             
             
 			// Number of members in group
diff --git a/main/group/group_category.php b/main/group/group_category.php
index 0ee6c10e1e..d8924acb27 100644
--- a/main/group/group_category.php
+++ b/main/group/group_category.php
@@ -15,8 +15,6 @@ $current_course_tool  = TOOL_GROUP;
 // Notice for unauthorized people.
 api_protect_course_script(true);
 
-require_once api_get_path(LIBRARY_PATH).'groupmanager.lib.php';
-
 if (!api_is_allowed_to_edit(false,true) || !(isset ($_GET['id']) || isset ($_POST['id']) || isset ($_GET['action']) || isset ($_POST['action']))) {
 	api_not_allowed();
 }
@@ -26,7 +24,7 @@ if (!api_is_allowed_to_edit(false,true) || !(isset ($_GET['id']) || isset ($_POS
  */
 function check_max_number_of_members($value) {
 	$max_member_no_limit = $value['max_member_no_limit'];
-	if ($max_member_no_limit == MEMBER_PER_GROUP_NO_LIMIT) {
+	if ($max_member_no_limit == GroupManager::MEMBER_PER_GROUP_NO_LIMIT) {
 		return true;
 	}
 	$max_member = $value['max_member'];
@@ -38,7 +36,7 @@ function check_max_number_of_members($value) {
  */
 function check_groups_per_user($value) {
 	$groups_per_user = $value['groups_per_user'];
-	if (isset ($_POST['id']) && intval($groups_per_user) != GROUP_PER_MEMBER_NO_LIMIT && GroupManager :: get_current_max_groups_per_user($_POST['id']) > intval($groups_per_user)) {
+	if (isset ($_POST['id']) && intval($groups_per_user) != GroupManager::GROUP_PER_MEMBER_NO_LIMIT && GroupManager::get_current_max_groups_per_user($_POST['id']) > intval($groups_per_user)) {
 		return false;
 	}
 	return true;
@@ -51,7 +49,16 @@ if (api_get_setting('allow_group_categories') == 'true') {
 	} else {
 		$nameTools = get_lang('AddCategory');
 		// Default values for new category
-		$category = array ('groups_per_user' => 1, 'doc_state' => TOOL_PRIVATE, 'work_state' => TOOL_PRIVATE, 'wiki_state' => TOOL_PRIVATE , 'chat_state' => TOOL_PRIVATE, 'calendar_state' => TOOL_PRIVATE, 'announcements_state'=> TOOL_PRIVATE, 'forum_state' => TOOL_PRIVATE, 'max_student' => 0);
+		$category = array(
+            'groups_per_user' => 1, 
+            'doc_state' => GroupManager::TOOL_PRIVATE, 
+            'work_state' => GroupManager::TOOL_PRIVATE, 
+            'wiki_state' => GroupManager::TOOL_PRIVATE , 
+            'chat_state' => GroupManager::TOOL_PRIVATE, 
+            'calendar_state' => GroupManager::TOOL_PRIVATE, 
+            'announcements_state'=> GroupManager::TOOL_PRIVATE, 
+            'forum_state' => GroupManager::TOOL_PRIVATE, 
+            'max_student' => 0);
 	}
 } else {
 	$category = GroupManager :: get_category($_GET['id']);
@@ -102,7 +109,7 @@ $possible_values = array ();
 for ($i = 1; $i <= 10; $i ++) {
 	$possible_values[$i] = $i;
 }
-$possible_values[GROUP_PER_MEMBER_NO_LIMIT] = get_lang('All');
+$possible_values[GroupManager::GROUP_PER_MEMBER_NO_LIMIT] = get_lang('All');
 $group[] = & $form->createElement('select', 'groups_per_user', null, $possible_values);
 $group[] = & $form->createElement('static', null, null, get_lang('QtyOfUserCanSubscribe_PartAfterNumber'));
 $form->addGroup($group, 'limit_group', get_lang('GroupLimit'), ' ', false);
@@ -114,7 +121,7 @@ $form->addElement('html', '<br /><br /><div class="sectiontitle" >'.get_lang('De
 $form->addElement('html', '</div>');
 
 // Members per group
-$form->addElement('radio', 'max_member_no_limit', get_lang('GroupLimit'), get_lang('NoLimit'), MEMBER_PER_GROUP_NO_LIMIT);
+$form->addElement('radio', 'max_member_no_limit', get_lang('GroupLimit'), get_lang('NoLimit'), GroupManager::MEMBER_PER_GROUP_NO_LIMIT);
 $group = array ();
 $group[] = & $form->createElement('radio', 'max_member_no_limit', null, get_lang('MaximumOfParticipants'), 1);
 $group[] = & $form->createElement('text', 'max_member', null, array ('size' => 2));
@@ -127,39 +134,39 @@ $form->addElement('checkbox', 'self_reg_allowed', get_lang('GroupSelfRegistratio
 $form->addElement('checkbox', 'self_unreg_allowed', null, get_lang('GroupAllowStudentUnregistration'), 1);
 
 // Documents settings
-$form->addElement('radio', 'doc_state', get_lang('GroupDocument'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$form->addElement('radio', 'doc_state', null, get_lang('Public'), TOOL_PUBLIC);
-$form->addElement('radio', 'doc_state', null, get_lang('Private'), TOOL_PRIVATE);
+$form->addElement('radio', 'doc_state', get_lang('GroupDocument'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$form->addElement('radio', 'doc_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$form->addElement('radio', 'doc_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 
 // Work settings
-$form->addElement('radio', 'work_state', get_lang('GroupWork'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$form->addElement('radio', 'work_state', null, get_lang('Public'), TOOL_PUBLIC);
-$form->addElement('radio', 'work_state', null, get_lang('Private'), TOOL_PRIVATE);
+$form->addElement('radio', 'work_state', get_lang('GroupWork'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$form->addElement('radio', 'work_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$form->addElement('radio', 'work_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 
 // Calendar settings
-$form->addElement('radio', 'calendar_state', get_lang('GroupCalendar'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$form->addElement('radio', 'calendar_state', null, get_lang('Public'), TOOL_PUBLIC);
-$form->addElement('radio', 'calendar_state', null, get_lang('Private'), TOOL_PRIVATE);
+$form->addElement('radio', 'calendar_state', get_lang('GroupCalendar'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$form->addElement('radio', 'calendar_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$form->addElement('radio', 'calendar_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 
 // Announcements settings
-$form->addElement('radio', 'announcements_state', get_lang('GroupAnnouncements'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$form->addElement('radio', 'announcements_state', null, get_lang('Public'), TOOL_PUBLIC);
-$form->addElement('radio', 'announcements_state', null, get_lang('Private'), TOOL_PRIVATE);
+$form->addElement('radio', 'announcements_state', get_lang('GroupAnnouncements'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$form->addElement('radio', 'announcements_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$form->addElement('radio', 'announcements_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 
 // Forum settings
-$form->addElement('radio', 'forum_state', get_lang('GroupForum'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$form->addElement('radio', 'forum_state', null, get_lang('Public'), TOOL_PUBLIC);
-$form->addElement('radio', 'forum_state', null, get_lang('Private'), TOOL_PRIVATE);
+$form->addElement('radio', 'forum_state', get_lang('GroupForum'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$form->addElement('radio', 'forum_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$form->addElement('radio', 'forum_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 
 // Wiki Settings
-$form->addElement('radio', 'wiki_state', get_lang('GroupWiki'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$form->addElement('radio', 'wiki_state', null, get_lang('Public'), TOOL_PUBLIC);
-$form->addElement('radio', 'wiki_state', null, get_lang('Private'), TOOL_PRIVATE);
+$form->addElement('radio', 'wiki_state', get_lang('GroupWiki'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$form->addElement('radio', 'wiki_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$form->addElement('radio', 'wiki_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 
 // Chat Settings
-$form->addElement('radio', 'chat_state', get_lang('Chat'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$form->addElement('radio', 'chat_state', null, get_lang('Public'), TOOL_PUBLIC);
-$form->addElement('radio', 'chat_state', null, get_lang('Private'), TOOL_PRIVATE);
+$form->addElement('radio', 'chat_state', get_lang('Chat'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$form->addElement('radio', 'chat_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$form->addElement('radio', 'chat_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 
 // Submit
 $form->addElement('style_submit_button', 'submit', get_lang('PropModify'), 'class="save"');
@@ -167,8 +174,8 @@ $form->addElement('style_submit_button', 'submit', get_lang('PropModify'), 'clas
 // If form validates -> save data
 if ($form->validate()) {
 	$values = $form->exportValues();
-	if ($values['max_member_no_limit'] == MEMBER_PER_GROUP_NO_LIMIT) {
-		$max_member = MEMBER_PER_GROUP_NO_LIMIT;
+	if ($values['max_member_no_limit'] == GroupManager::MEMBER_PER_GROUP_NO_LIMIT) {
+		$max_member = GroupManager::MEMBER_PER_GROUP_NO_LIMIT;
 	} else {
 		$max_member = $values['max_member'];
 	}
@@ -198,8 +205,8 @@ echo '</div>';
 
 $defaults = $category;
 $defaults['action'] = $action;
-if ($defaults['max_student'] == MEMBER_PER_GROUP_NO_LIMIT) {
-	$defaults['max_member_no_limit'] = MEMBER_PER_GROUP_NO_LIMIT;
+if ($defaults['max_student'] == GroupManager::MEMBER_PER_GROUP_NO_LIMIT) {
+	$defaults['max_member_no_limit'] = GroupManager::MEMBER_PER_GROUP_NO_LIMIT;
 } else {
 	$defaults['max_member_no_limit'] = 1;
 	$defaults['max_member'] = $defaults['max_student'];
diff --git a/main/group/group_creation.php b/main/group/group_creation.php
index f51c5382cd..eb95bb1870 100644
--- a/main/group/group_creation.php
+++ b/main/group/group_creation.php
@@ -43,7 +43,7 @@ if (isset ($_POST['action'])) {
 					$group['places'] = $_POST['group_0_places'];
 				}
 				if (api_get_setting('allow_group_categories') == 'false') {
-					$group['category'] = DEFAULT_GROUP_CATEGORY;
+					$group['category'] = GroupManager::DEFAULT_GROUP_CATEGORY;
 				} elseif ($_POST['same_category']) {
 					$group['category'] = $_POST['group_0_category'];
 				}
@@ -135,7 +135,7 @@ elseif (isset($_POST['number_of_groups'])) {
 		$group_id = GroupManager :: get_number_of_groups() + 1;
 		foreach ($group_categories as $index => $category) {
 			// Don't allow new groups in the virtual course category!
-			if ($category['id'] != VIRTUAL_COURSE_CATEGORY) {
+			if ($category['id'] != GroupManager::VIRTUAL_COURSE_CATEGORY) {
 				$cat_options[$category['id']] = $category['title'];
 			}
 		}
@@ -310,7 +310,7 @@ EOT;
 			$cat_options = array ();
 			foreach ($group_categories as $index => $category) {
 				// Don't allow new groups in the virtual course category!
-				if ($category['id'] != VIRTUAL_COURSE_CATEGORY) {
+				if ($category['id'] != GroupManager::VIRTUAL_COURSE_CATEGORY) {
 					$cat_options[$category['id']] = $category['title'];
 				}
 			}
diff --git a/main/group/group_edit.php b/main/group/group_edit.php
index 09da332c91..c393c99336 100644
--- a/main/group/group_edit.php
+++ b/main/group/group_edit.php
@@ -90,7 +90,7 @@ function sort_users($user_a, $user_b) {
  */
 function check_max_number_of_members($value) {
 	$max_member_no_limit = $value['max_member_no_limit'];
-	if ($max_member_no_limit == MEMBER_PER_GROUP_NO_LIMIT) {
+	if ($max_member_no_limit == GroupManager::MEMBER_PER_GROUP_NO_LIMIT) {
 		return true;
 	}
 	$max_member = $value['max_member'];
@@ -101,7 +101,7 @@ function check_max_number_of_members($value) {
  * Function to check if the number of selected group members is valid
  */
 function check_group_members($value) {
-	if ($value['max_member_no_limit'] == MEMBER_PER_GROUP_NO_LIMIT) {
+	if ($value['max_member_no_limit'] == GroupManager::MEMBER_PER_GROUP_NO_LIMIT) {
 		return true;
 	}
 	if (isset($value['max_member']) && isset($value['group_members']) && $value['max_member'] < count($value['group_members'])) {
@@ -207,7 +207,7 @@ $form->addFormRule('check_group_members');
 //$form->addGroup($group, 'tutor_group', get_lang('GroupTutor'), '', false);
 
 // Members per group
-$form->addElement('radio', 'max_member_no_limit', get_lang('GroupLimit'), get_lang('NoLimit'), MEMBER_PER_GROUP_NO_LIMIT);
+$form->addElement('radio', 'max_member_no_limit', get_lang('GroupLimit'), get_lang('NoLimit'), GroupManager::MEMBER_PER_GROUP_NO_LIMIT);
 $group = array();
 $group[] = & $form->createElement('radio', 'max_member_no_limit', null, get_lang('MaximumOfParticipants'), 1);
 $group[] = & $form->createElement('text', 'max_member', null, array('class' => 'span1'));
@@ -223,52 +223,52 @@ $form->addGroup($group, '', Display::return_icon('user.png', get_lang('GroupSelf
 
 // Documents settings
 $group = array();
-$group[] = $form->createElement('radio', 'doc_state', get_lang('GroupDocument'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$group[] = $form->createElement('radio', 'doc_state', null, get_lang('Public'), TOOL_PUBLIC);
-$group[] = $form->createElement('radio', 'doc_state', null, get_lang('Private'), TOOL_PRIVATE);
+$group[] = $form->createElement('radio', 'doc_state', get_lang('GroupDocument'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$group[] = $form->createElement('radio', 'doc_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$group[] = $form->createElement('radio', 'doc_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 $form->addGroup($group, '', Display::return_icon('folder.png', get_lang('GroupDocument') , array(), ICON_SIZE_SMALL).' '.get_lang('GroupDocument'), '', false);
 
 // Work settings
 $group = array();
-$group[] = $form->createElement('radio', 'work_state', get_lang('GroupWork'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$group[] = $form->createElement('radio', 'work_state', null, get_lang('Public'), TOOL_PUBLIC);
-$group[] = $form->createElement('radio', 'work_state', null, get_lang('Private'), TOOL_PRIVATE);
+$group[] = $form->createElement('radio', 'work_state', get_lang('GroupWork'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$group[] = $form->createElement('radio', 'work_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$group[] = $form->createElement('radio', 'work_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 $form->addGroup($group, '', Display::return_icon('work.png', get_lang('GroupWork') , array(), ICON_SIZE_SMALL).' '.get_lang('GroupWork'), '', false);
 
 
 // Calendar settings
 $group = array();
-$group[] = $form->createElement('radio', 'calendar_state', get_lang('GroupCalendar'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$group[] = $form->createElement('radio', 'calendar_state', null, get_lang('Public'), TOOL_PUBLIC);
-$group[] = $form->createElement('radio', 'calendar_state', null, get_lang('Private'), TOOL_PRIVATE);
+$group[] = $form->createElement('radio', 'calendar_state', get_lang('GroupCalendar'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$group[] = $form->createElement('radio', 'calendar_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$group[] = $form->createElement('radio', 'calendar_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 $form->addGroup($group, '', Display::return_icon('agenda.png', get_lang('GroupCalendar') , array(), ICON_SIZE_SMALL).' '.get_lang('GroupCalendar'), '', false);
 
 // Announcements settings
 $group = array();
-$group[] = $form->createElement('radio', 'announcements_state', get_lang('GroupAnnouncements'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$group[] = $form->createElement('radio', 'announcements_state', null, get_lang('Public'), TOOL_PUBLIC);
-$group[] = $form->createElement('radio', 'announcements_state', null, get_lang('Private'), TOOL_PRIVATE);
+$group[] = $form->createElement('radio', 'announcements_state', get_lang('GroupAnnouncements'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$group[] = $form->createElement('radio', 'announcements_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$group[] = $form->createElement('radio', 'announcements_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 $form->addGroup($group, '', Display::return_icon('announce.png', get_lang('GroupAnnouncements') , array(), ICON_SIZE_SMALL).' '.get_lang('GroupAnnouncements'), '', false);
 
 //Forum settings
 $group = array();
-$group[] = $form->createElement('radio', 'forum_state', get_lang('GroupForum'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$group[] = $form->createElement('radio', 'forum_state', null, get_lang('Public'), TOOL_PUBLIC);
-$group[] = $form->createElement('radio', 'forum_state', null, get_lang('Private'), TOOL_PRIVATE);
+$group[] = $form->createElement('radio', 'forum_state', get_lang('GroupForum'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$group[] = $form->createElement('radio', 'forum_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$group[] = $form->createElement('radio', 'forum_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 $form->addGroup($group, '', Display::return_icon('forum.png', get_lang('GroupForum') , array(), ICON_SIZE_SMALL).' '.get_lang('GroupForum'), '', false);
 
 // Wiki settings
 $group = array();
-$group[] = $form->createElement('radio', 'wiki_state', get_lang('GroupWiki'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$group[] = $form->createElement('radio', 'wiki_state', null, get_lang('Public'), TOOL_PUBLIC);
-$group[] = $form->createElement('radio', 'wiki_state', null, get_lang('Private'), TOOL_PRIVATE);
+$group[] = $form->createElement('radio', 'wiki_state', get_lang('GroupWiki'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$group[] = $form->createElement('radio', 'wiki_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$group[] = $form->createElement('radio', 'wiki_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 $form->addGroup($group, '', Display::return_icon('wiki.png', get_lang('GroupWiki') , array(), ICON_SIZE_SMALL).' '.get_lang('GroupWiki'), '', false);
 
 // Chat settings
 $group = array();
-$group[] = $form->createElement('radio', 'chat_state', get_lang('Chat'), get_lang('NotAvailable'), TOOL_NOT_AVAILABLE);
-$group[] = $form->createElement('radio', 'chat_state', null, get_lang('Public'), TOOL_PUBLIC);
-$group[] = $form->createElement('radio', 'chat_state', null, get_lang('Private'), TOOL_PRIVATE);
+$group[] = $form->createElement('radio', 'chat_state', get_lang('Chat'), get_lang('NotAvailable'), GroupManager::TOOL_NOT_AVAILABLE);
+$group[] = $form->createElement('radio', 'chat_state', null, get_lang('Public'), GroupManager::TOOL_PUBLIC);
+$group[] = $form->createElement('radio', 'chat_state', null, get_lang('Private'), GroupManager::TOOL_PRIVATE);
 $form->addGroup($group, '', Display::return_icon('chat.png', get_lang('Chat') , array(), ICON_SIZE_SMALL).' '.get_lang('Chat'), '', false);
 
 // submit button
@@ -276,8 +276,8 @@ $form->addElement('style_submit_button', 'submit', get_lang('PropModify'), 'clas
 
 if ($form->validate()) {
 	$values = $form->exportValues();
-	if ($values['max_member_no_limit'] == MEMBER_PER_GROUP_NO_LIMIT) {
-		$max_member = MEMBER_PER_GROUP_NO_LIMIT;
+	if ($values['max_member_no_limit'] == GroupManager::MEMBER_PER_GROUP_NO_LIMIT) {
+		$max_member = GroupManager::MEMBER_PER_GROUP_NO_LIMIT;
 	} else {
 		$max_member = $values['max_member'];
 	}
@@ -298,9 +298,9 @@ if ($form->validate()) {
 	}
 
 	// Returning to the group area (note: this is inconsistent with the rest of chamilo)
-    //var_dump(count($_POST['group_members']), $max_member, MEMBER_PER_GROUP_NO_LIMIT);
+    //var_dump(count($_POST['group_members']), $max_member, GroupManager::MEMBER_PER_GROUP_NO_LIMIT);
 	$cat = GroupManager :: get_category_from_group($current_group['id']);      
-    if (isset($_POST['group_members']) && count($_POST['group_members']) > $max_member && $max_member != MEMBER_PER_GROUP_NO_LIMIT) {
+    if (isset($_POST['group_members']) && count($_POST['group_members']) > $max_member && $max_member != GroupManager::MEMBER_PER_GROUP_NO_LIMIT) {
         header('Location:group_edit.php?show_message='.get_lang('GroupTooMuchMembers'));
     } else {
         header('Location: '.$values['referer'].'?action=show_msg&msg='.get_lang('GroupSettingsModified').'&category='.$cat['id']);
@@ -312,8 +312,8 @@ $defaults['group_members'] = $selected_users;
 $defaults['group_tutors'] = $selected_tutors;
 $action = isset($_GET['action']) ? $_GET['action'] : '';
 $defaults['action'] = $action;
-if ($defaults['maximum_number_of_students'] == MEMBER_PER_GROUP_NO_LIMIT) {
-	$defaults['max_member_no_limit'] = MEMBER_PER_GROUP_NO_LIMIT;
+if ($defaults['maximum_number_of_students'] == GroupManager::MEMBER_PER_GROUP_NO_LIMIT) {
+	$defaults['max_member_no_limit'] = GroupManager::MEMBER_PER_GROUP_NO_LIMIT;
 } else {
 	$defaults['max_member_no_limit'] = 1;
 	$defaults['max_member'] = $defaults['maximum_number_of_students'];
diff --git a/main/group/group_space.php b/main/group/group_space.php
index c193a4fab9..2ff27a6e8c 100644
--- a/main/group/group_space.php
+++ b/main/group/group_space.php
@@ -143,7 +143,7 @@ if (api_is_allowed_to_edit(false, true) OR GroupManager :: is_user_in_group(api_
 	$forums_of_groups = get_forums_of_group($current_group['id']);
     
 	if (is_array($forums_of_groups)) {
-		if ($current_group['forum_state'] != TOOL_NOT_AVAILABLE ) {
+		if ($current_group['forum_state'] != GroupManager::TOOL_NOT_AVAILABLE ) {
 			foreach ($forums_of_groups as $key => $value) {
 				if ($value['forum_group_public_private'] == 'public' || (/*!empty($user_subscribe_to_current_group) && */ $value['forum_group_public_private'] == 'private') || !empty($user_is_tutor) || api_is_allowed_to_edit(false, true)) {
 					$tools .= '<li style="display:inline; margin:5px;"><a href="../forum/viewforum.php?forum='.$value['forum_id'].'&gidReq='.Security::remove_XSS($current_group['id']).'&amp;origin=group">'.Display::return_icon('forum.png', get_lang('Forum').': '.$value['forum_title'] , array(), 32).'</a></li>';
@@ -151,27 +151,27 @@ if (api_is_allowed_to_edit(false, true) OR GroupManager :: is_user_in_group(api_
 			}
 		}
 	}
-	if ($current_group['doc_state'] != TOOL_NOT_AVAILABLE ) {
+	if ($current_group['doc_state'] != GroupManager::TOOL_NOT_AVAILABLE ) {
 		// Link to the documents area of this group
 		$tools .= '<li style="display:inline; margin:5px;" ><a href="../document/document.php?'.api_get_cidreq().'&amp;gidReq='.$current_group['id'].'">'.Display::return_icon('folder.png', get_lang('GroupDocument'), array(), 32).'</a></li>';
 	}
-	if ($current_group['calendar_state'] != TOOL_NOT_AVAILABLE) {
+	if ($current_group['calendar_state'] != GroupManager::TOOL_NOT_AVAILABLE) {
 		// Link to a group-specific part of agenda
 		$tools .= '<li style="display:inline; margin:5px;"><a href="../calendar/agenda.php?'.api_get_cidreq().'&amp;toolgroup='.$current_group['id'].'&amp;group='.$current_group['id'].'&amp;acces=0">'.Display::return_icon('agenda.png', get_lang('GroupCalendar'), array(), 32).'</a></li>';
 	}
-	if ($current_group['work_state'] != TOOL_NOT_AVAILABLE) {
+	if ($current_group['work_state'] != GroupManager::TOOL_NOT_AVAILABLE) {
 		// Link to the works area of this group
 		$tools .= '<li style="display:inline; margin:5px;" ><a href="../work/work.php?'.api_get_cidreq().'&amp;toolgroup='.$current_group['id'].'">'.Display::return_icon('work.png', get_lang('GroupWork'), array(), 32).'</a></li>';
 	}
-	if ($current_group['announcements_state'] != TOOL_NOT_AVAILABLE) {
+	if ($current_group['announcements_state'] != GroupManager::TOOL_NOT_AVAILABLE) {
 		// Link to a group-specific part of announcements
 		$tools .= '<li style="display:inline; margin:5px;"><a href="../announcements/announcements.php?'.api_get_cidreq().'&amp;toolgroup='.$current_group['id'].'">'.Display::return_icon('announce.png', get_lang('GroupAnnouncements'), array(), 32).'</a></li>';
 	}
-	if ($current_group['wiki_state'] != TOOL_NOT_AVAILABLE) {
+	if ($current_group['wiki_state'] != GroupManager::TOOL_NOT_AVAILABLE) {
 		// Link to the wiki area of this group
 		$tools .= '<li style="display:inline; margin:5px;"><a href="../wiki/index.php?'.api_get_cidreq().'&amp;toolgroup='.$current_group['id'].'&amp;action=show&amp;title=index&amp;session_id='.api_get_session_id().'&amp;group_id='.$current_group['id'].'">'.Display::return_icon('wiki.png', get_lang('GroupWiki'), array(), 32).'</a></li>';
 	}
-	if ($current_group['chat_state'] != TOOL_NOT_AVAILABLE) {
+	if ($current_group['chat_state'] != GroupManager::TOOL_NOT_AVAILABLE) {
 		// Link to the chat area of this group
 		if (api_get_course_setting('allow_open_chat_window')) {
 			$tools .= "<li style=\"display:inline; margin:5px;\"><a href=\"javascript: void(0);\" onclick=\"window.open('../chat/chat.php?".api_get_cidreq()."&amp;toolgroup=".$current_group['id']."','window_chat_group_".$_SESSION['_cid']."_".$_SESSION['_gid']."','height=380, width=625, left=2, top=2, toolbar=no, menubar=no, scrollbars=yes, resizable=yes, location=no, directories=no, status=no') \" >".Display::return_icon('chat.png', get_lang('Chat'),'',ICON_SIZE_MEDIUM)."</a></li>";
@@ -192,7 +192,7 @@ echo '</ul>';
 	// Link to the forum of this group
 	$forums_of_groups = get_forums_of_group($current_group['id']);
 	if (is_array($forums_of_groups)) {
-		if ( $current_group['forum_state'] == TOOL_PUBLIC ) {
+		if ( $current_group['forum_state'] == GroupManager::TOOL_PUBLIC ) {
 			foreach ($forums_of_groups as $key => $value) {
 				if ($value['forum_group_public_private'] == 'public' ) {
 					$tools.= '<li style="display:inline; margin:5px;"><a href="../forum/viewforum.php?forum='.$value['forum_id'].'&gidReq='.Security::remove_XSS($current_group['id']).'&amp;origin=group">'.Display::return_icon('forum.png', get_lang('GroupForum'), array(), 32).'</a></li>';
@@ -200,27 +200,27 @@ echo '</ul>';
 			}
 		}
 	}
-	if ($current_group['doc_state'] == TOOL_PUBLIC) {
+	if ($current_group['doc_state'] == GroupManager::TOOL_PUBLIC) {
 		// Link to the documents area of this group
 		$tools .= '<li style="display:inline; margin:5px;"><a href="../document/document.php?'.api_get_cidreq().'&amp;gidReq='.$current_group['id'].'&amp;origin='.$origin.'">'.Display::return_icon('folder.png', get_lang('GroupDocument'), array(), 32).'</a></li>';
 	}
-	if ($current_group['calendar_state'] == TOOL_PUBLIC) {
+	if ($current_group['calendar_state'] == GroupManager::TOOL_PUBLIC) {
 		// Link to a group-specific part of agenda
 		$tools .= '<li style="display:inline; margin:5px;"><a href="../calendar/agenda.php?'.api_get_cidreq().'&amp;toolgroup='.$current_group['id'].'&amp;group='.$current_group['id'].'">'.Display::return_icon('agenda.png', get_lang('GroupCalendar'), array(), 32).'</a></li>';
 	}
-	if ($current_group['work_state'] == TOOL_PUBLIC) {
+	if ($current_group['work_state'] == GroupManager::TOOL_PUBLIC) {
 		// Link to the works area of this group
 		$tools .= '<li style="display:inline; margin:5px;"><a href="../work/work.php?'.api_get_cidreq().'&amp;toolgroup='.$current_group['id'].'">'.Display::return_icon('work.png', get_lang('GroupWork'), array(), 32).'</a></li>';
 	}
-	if ($current_group['announcements_state'] == TOOL_PUBLIC) {
+	if ($current_group['announcements_state'] == GroupManager::TOOL_PUBLIC) {
 		// Link to a group-specific part of announcements
 		$tools .= '<li style="display:inline; margin:5px;"><a href="../announcements/announcements.php?'.api_get_cidreq().'&amp;toolgroup='.$current_group['id'].'&amp;group='.$current_group['id'].'">'.Display::return_icon('announce.png', get_lang('GroupAnnouncements'), array(), 32).'</a></li>';
 	}
-	if ($current_group['wiki_state'] == TOOL_PUBLIC) {
+	if ($current_group['wiki_state'] == GroupManager::TOOL_PUBLIC) {
 		// Link to the wiki area of this group
 		$tools .= '<li style="display:inline; margin:5px;"><a href="../wiki/index.php?'.api_get_cidreq().'&amp;toolgroup='.$current_group['id'].'&amp;action=show&amp;title=index&amp;session_id='.api_get_session_id().'&amp;group_id='.$current_group['id'].'">'.Display::return_icon('wiki.png', get_lang('GroupWiki'), array(), 32).'</a></li>';		
 	}
-	if ($current_group['chat_state'] == TOOL_PUBLIC ) {
+	if ($current_group['chat_state'] == GroupManager::TOOL_PUBLIC ) {
 		// Link to the chat area of this group
 		if (api_get_course_setting('allow_open_chat_window')) {
 			$tools .= "<li style=\"display:inline; margin:5px;\"><a href=\"javascript: void(0);\" onclick=\"window.open('../chat/chat.php?".api_get_cidreq()."&amp;toolgroup=".$current_group['id']."','window_chat_group_".$_SESSION['_cid']."_".$_SESSION['_gid']."','height=380, width=625, left=2, top=2, toolbar=no, menubar=no, scrollbars=yes, resizable=yes, location=no, directories=no, status=no') \" >".Display::return_icon('chat.png', get_lang("Chat"), array(), 32)."</a></li>";
diff --git a/main/inc/lib/groupmanager.lib.php b/main/inc/lib/groupmanager.lib.php
index 1fec8ea884..531ac04822 100644
--- a/main/inc/lib/groupmanager.lib.php
+++ b/main/inc/lib/groupmanager.lib.php
@@ -12,47 +12,6 @@ require_once 'fileManage.lib.php';
 require_once 'fileUpload.lib.php';
 require_once 'document.lib.php';
 
-/**
- * infinite
- */
-define("INFINITE", "99999");
-/**
- * No limit on the number of users in a group
- */
-define("MEMBER_PER_GROUP_NO_LIMIT", "0");
-/**
- * No limit on the number of groups per user
- */
-define("GROUP_PER_MEMBER_NO_LIMIT", "0");
-/**
- * The tools of a group can have 3 states
- * - not available
- * - public
- * - private
- */
-define("TOOL_NOT_AVAILABLE", "0");
-define("TOOL_PUBLIC", "1");
-define("TOOL_PRIVATE", "2");
-/**
- * Constants for the available group tools
- */
-define("GROUP_TOOL_FORUM", "0");
-define("GROUP_TOOL_DOCUMENTS", "1");
-define("GROUP_TOOL_CALENDAR","2");
-define("GROUP_TOOL_ANNOUNCEMENT","3");
-define("GROUP_TOOL_WORK","4");
-define("GROUP_TOOL_WIKI", "5");
-define("GROUP_TOOL_CHAT", "6");
-
-/**
- * Fixed id's for group categories
- * - VIRTUAL_COURSE_CATEGORY: in this category groups are created based on the
- *   virtual  course of a course
- * - DEFAULT_GROUP_CATEGORY: When group categories aren't available (platform-
- *   setting),  all groups are created in this 'dummy'-category
- */
-define("VIRTUAL_COURSE_CATEGORY", 1);
-define("DEFAULT_GROUP_CATEGORY", 2);
 /**
  * This library contains some functions for group-management.
  * @author Bart Mollet
@@ -61,6 +20,49 @@ define("DEFAULT_GROUP_CATEGORY", 2);
  * be used outside a session.
  */
 class GroupManager {
+    //- VIRTUAL_COURSE_CATEGORY: in this category groups are created based on the virtual  course of a course 
+    CONST VIRTUAL_COURSE_CATEGORY = 1;
+    
+    //DEFAULT_GROUP_CATEGORY: When group categories aren't available (platform-setting),  all groups are created in this 'dummy'-category
+    CONST DEFAULT_GROUP_CATEGORY = 2;
+    
+    /**
+     * infinite
+     */
+    CONST INFINITE  = 99999;
+    /**
+     * No limit on the number of users in a group
+     */
+    CONST MEMBER_PER_GROUP_NO_LIMIT = 0;
+    /**
+     * No limit on the number of groups per user
+     */
+    CONST GROUP_PER_MEMBER_NO_LIMIT = 0;
+    /**
+     * The tools of a group can have 3 states
+     * - not available
+     * - public
+     * - private
+     */
+    CONST TOOL_NOT_AVAILABLE = 0;
+    CONST TOOL_PUBLIC = 1;
+    CONST TOOL_PRIVATE = 2;
+    /**
+     * Constants for the available group tools
+     */
+    CONST GROUP_TOOL_FORUM = 0;
+    CONST GROUP_TOOL_DOCUMENTS = 1;
+    CONST GROUP_TOOL_CALENDAR = 2;
+    CONST GROUP_TOOL_ANNOUNCEMENT = 3;
+    CONST GROUP_TOOL_WORK = 4;
+    CONST GROUP_TOOL_WIKI = 5;
+    CONST GROUP_TOOL_CHAT = 6;
+    
+    
+    
+    
+    
+    
 	//GROUP FUNCTIONS
 	private function __construct() {		
 	}
@@ -173,7 +175,7 @@ class GroupManager {
 		$groups = array ();
 		$thisGroup= array();
 			while ($thisGroup = Database::fetch_array($groupList)) {
-				if ($thisGroup['category_id'] == VIRTUAL_COURSE_CATEGORY) {
+				if ($thisGroup['category_id'] == self::VIRTUAL_COURSE_CATEGORY) {
 					$sql = "SELECT title FROM $table_course WHERE code = '".$thisGroup['name']."'";
 					$obj = Database::fetch_object(Database::query($sql));
 					$thisGroup['name'] = $obj->title;
@@ -288,7 +290,7 @@ class GroupManager {
 	public static function create_subgroups ($group_id, $number_of_groups) {
 		$course_id = api_get_course_int_id();
 		$table_group = Database :: get_course_table(TABLE_GROUP);
-		$category_id = self :: create_category('Subgroups', '', TOOL_PRIVATE, TOOL_PRIVATE, 0, 0, 1, 1);
+		$category_id = self :: create_category('Subgroups', '', GroupManager::TOOL_PRIVATE, GroupManager::TOOL_PRIVATE, 0, 0, 1, 1);
 		$users = self :: get_users($group_id);
 		$group_ids = array ();
 
@@ -310,12 +312,12 @@ class GroupManager {
 	 * Create groups from all virtual courses in the given course.
 	 */
 	public static function create_groups_from_virtual_courses() {
-		self :: delete_category(VIRTUAL_COURSE_CATEGORY);
-		$id = self :: create_category(get_lang('GroupsFromVirtualCourses'), '', TOOL_NOT_AVAILABLE, TOOL_NOT_AVAILABLE, 0, 0, 1, 1);
+		self :: delete_category(self::VIRTUAL_COURSE_CATEGORY);
+		$id = self :: create_category(get_lang('GroupsFromVirtualCourses'), '', GroupManager::TOOL_NOT_AVAILABLE, GroupManager::TOOL_NOT_AVAILABLE, 0, 0, 1, 1);
 		$table_group_cat = Database :: get_course_table(TABLE_GROUP_CATEGORY);
         $course_id = api_get_course_int_id();
         
-		$sql = "UPDATE ".$table_group_cat." SET id=".VIRTUAL_COURSE_CATEGORY." WHERE c_id = $course_id AND id=$id";
+		$sql = "UPDATE ".$table_group_cat." SET id=".self::VIRTUAL_COURSE_CATEGORY." WHERE c_id = $course_id AND id=$id";
 		Database::query($sql);
 		$course = api_get_course_info();
 		$course['code'] = $course['sysCode'];
@@ -332,7 +334,7 @@ class GroupManager {
 					$members[] = $user['user_id'];
 				}
 			}
-			$id = self :: create_group($group_course['code'], VIRTUAL_COURSE_CATEGORY, 0, count($members));
+			$id = self :: create_group($group_course['code'], self::VIRTUAL_COURSE_CATEGORY, 0, count($members));
 			self :: subscribe_users($members, $id);
 			$ids[] = $id;
 		}
@@ -668,7 +670,7 @@ class GroupManager {
 					max_student = '".Database::escape_string($maximum_number_of_students)."' ";
 		Database::query($sql);
 		$id = Database::insert_id();
-		if ($id == VIRTUAL_COURSE_CATEGORY) {
+		if ($id == self::VIRTUAL_COURSE_CATEGORY) {
 			$sql = "UPDATE  ".$table_group_category." SET id = ". ($id +1)." WHERE c_id = $course_id AND id = $id";
 			Database::query($sql);
 			return $id +1;
@@ -848,8 +850,10 @@ class GroupManager {
 	 * @return void
 	 */
 	public static function fill_groups ($group_ids) {
+        global $_course;
+        
 		$group_ids = is_array($group_ids) ? $group_ids : array ($group_ids);
-		$group_ids = array_map('intval',$group_ids);
+		$group_ids = array_map('intval', $group_ids);
         
 		if (api_is_course_coach()) {
 			for ($i=0 ; $i< count($group_ids) ; $i++) {
@@ -862,8 +866,7 @@ class GroupManager {
 				return false;                
             }
 		}
-
-		global $_course;
+     		
 		$category 			= self::get_category_from_group($group_ids[0]);
         
 		$groups_per_user 	= $category['groups_per_user'];		
@@ -871,25 +874,23 @@ class GroupManager {
 		$group_user_table 	= Database :: get_course_table(TABLE_GROUP_USER);
 		$session_id 		= api_get_session_id();
 		
-		$complete_user_list = CourseManager :: get_real_and_linked_user_list($_course['code'], true, $session_id);				
-        $number_groups_per_user = ($groups_per_user == GROUP_PER_MEMBER_NO_LIMIT ? INFINITE : $groups_per_user);
+		$complete_user_list = CourseManager :: get_real_and_linked_user_list($_course['code'], true, $session_id);				        
+        $number_groups_per_user = ($groups_per_user == self::GROUP_PER_MEMBER_NO_LIMIT ? self::INFINITE : $groups_per_user);
         
 		/*
 		 * Retrieve all the groups where enrollment is still allowed
 		 * (reverse) ordered by the number of place available
 		 */
         
-        $course_id = api_get_course_int_id();
-        
+        $course_id = api_get_course_int_id();        
 		$sql = "SELECT g.id gid, g.max_student-count(ug.user_id) nbPlaces, g.max_student
 				FROM ".$group_table." g
-				LEFT JOIN  ".$group_user_table." ug
-				ON g.id = ug.group_id
-				WHERE 
-					g.c_id = $course_id AND							 
+				LEFT JOIN  ".$group_user_table." ug ON  
+                    g.c_id = $course_id AND ug.c_id = $course_id  AND g.id = ug.group_id
+				WHERE 					
 					g.id IN (".implode(',', $group_ids).")
 				GROUP BY (g.id)
-				HAVING (nbPlaces > 0 OR g.max_student = ".MEMBER_PER_GROUP_NO_LIMIT.")
+				HAVING (nbPlaces > 0 OR g.max_student = ".GroupManager::MEMBER_PER_GROUP_NO_LIMIT.")
 				ORDER BY nbPlaces DESC";
 		$sql_result = Database::query($sql);
 		$group_available_place = array ();
@@ -976,7 +977,7 @@ class GroupManager {
 		$db_result = Database::query("SELECT max_student FROM $table_group WHERE c_id = $course_id AND id = $group_id");
 		$db_object = Database::fetch_object($db_result);
 		if ($db_object->max_student == 0) {
-			return INFINITE;
+			return self::INFINITE;
 		}
 		return $db_object->max_student;
 	}
@@ -1072,8 +1073,8 @@ class GroupManager {
 		$result = CourseManager :: is_user_subscribed_in_real_or_linked_course($user_id, $course_code);
 		$result = !self :: is_subscribed($user_id, $group_id);
 		$result &= (self :: number_of_students($group_id) < self :: maximum_number_of_students($group_id));
-		if ($category['groups_per_user'] == GROUP_PER_MEMBER_NO_LIMIT) {
-			$category['groups_per_user'] = INFINITE;
+		if ($category['groups_per_user'] == self::GROUP_PER_MEMBER_NO_LIMIT) {
+			$category['groups_per_user'] = self::INFINITE;
 		}
 		$result &= (self :: user_in_number_of_groups($user_id, $category['id']) < $category['groups_per_user']);
 		$result &= !self :: is_tutor_of_group($user_id, $group_id);
@@ -1411,7 +1412,7 @@ class GroupManager {
 	public static function get_complete_list_of_users_that_can_be_added_to_group ($course_code, $group_id) {
 		global $_course, $_user;
 		$category = self :: get_category_from_group($group_id, $course_code);
-		$number_of_groups_limit = $category['groups_per_user'] == GROUP_PER_MEMBER_NO_LIMIT ? INFINITE : $category['groups_per_user'];
+		$number_of_groups_limit = $category['groups_per_user'] == self::GROUP_PER_MEMBER_NO_LIMIT ? self::INFINITE : $category['groups_per_user'];
 		$real_course_code = $_course['sysCode'];
 		$real_course_info = Database :: get_course_info($real_course_code);
 		$real_course_user_list = CourseManager :: get_user_list_from_course_code($real_course_code);
@@ -1535,25 +1536,25 @@ class GroupManager {
         }
         
 		switch ($tool) {
-			case GROUP_TOOL_FORUM :
+			case self::GROUP_TOOL_FORUM :
 				$state_key = 'forum_state';
 				break;
-			case GROUP_TOOL_DOCUMENTS :
+			case self::GROUP_TOOL_DOCUMENTS :
 				$state_key = 'doc_state';
 				break;
-			case GROUP_TOOL_CALENDAR :
+			case self::GROUP_TOOL_CALENDAR :
 				$state_key = 'calendar_state';
 				break;
-			case GROUP_TOOL_ANNOUNCEMENT :
+			case self::GROUP_TOOL_ANNOUNCEMENT :
 				$state_key = 'announcements_state';
 				break;
-			case GROUP_TOOL_WORK :
+			case self::GROUP_TOOL_WORK :
 				$state_key = 'work_state';
 				break;
-			case GROUP_TOOL_WIKI :
+			case self::GROUP_TOOL_WIKI :
 				$state_key = 'wiki_state';
 				break;
-			case GROUP_TOOL_CHAT :
+			case self::GROUP_TOOL_CHAT :
 				$state_key = 'chat_state';
 				break;
 			default:
@@ -1570,24 +1571,24 @@ class GroupManager {
         
         if (!empty($category_group_info)) {
             //if exists check the category group status first        
-            if ($category_group_info[$state_key] == TOOL_NOT_AVAILABLE) {
+            if ($category_group_info[$state_key] == GroupManager::TOOL_NOT_AVAILABLE) {
                 return false;                
-            } elseif($category_group_info[$state_key] == TOOL_PRIVATE && !$user_is_in_group) {                
+            } elseif($category_group_info[$state_key] == GroupManager::TOOL_PRIVATE && !$user_is_in_group) {                
                 return false;
             }
         }
         
         //is_user_in_group() is more complete that  the  is_subscribed() function        
         
-		if ($group_info[$state_key] == TOOL_NOT_AVAILABLE) {
+		if ($group_info[$state_key] == GroupManager::TOOL_NOT_AVAILABLE) {
 			return false;
-		} elseif ($group_info[$state_key] == TOOL_PUBLIC) {
+		} elseif ($group_info[$state_key] == self::TOOL_PUBLIC) {
 			return true;
 		} elseif (api_is_allowed_to_edit(false,true)) {
 			return true;
 		} elseif($group_info['tutor_id'] == $user_id) { //this tutor implementation was dropped
 			return true;		
-        } elseif($group_info[$state_key] == TOOL_PRIVATE && !$user_is_in_group) {
+        } elseif($group_info[$state_key] == GroupManager::TOOL_PRIVATE && !$user_is_in_group) {
             return false;
         } else {		
             return $user_is_in_group;
@@ -1647,7 +1648,7 @@ class GroupManager {
         $group_user_table = Database :: get_course_table(TABLE_GROUP_USER);
         $session_id = api_get_session_id();
         $complete_user_list = CourseManager :: get_real_and_linked_user_list($_course['sysCode'], true, $session_id);
-        $number_groups_per_user = ($groups_per_user == GROUP_PER_MEMBER_NO_LIMIT ? INFINITE : $groups_per_user);
+        $number_groups_per_user = ($groups_per_user == self::GROUP_PER_MEMBER_NO_LIMIT ? self::INFINITE : $groups_per_user);
         $course_id = api_get_course_int_id();
         /*
          * Retrieve all the groups where enrollment is still allowed
@@ -1661,7 +1662,7 @@ class GroupManager {
                         ug.c_id = $course_id AND 
                         g.id IN (".implode(',', $group_ids).")
                 GROUP BY (g.id)
-                HAVING (nbPlaces > 0 OR g.max_student = ".MEMBER_PER_GROUP_NO_LIMIT.")
+                HAVING (nbPlaces > 0 OR g.max_student = ".GroupManager::MEMBER_PER_GROUP_NO_LIMIT.")
                 ORDER BY nbPlaces DESC";
         $sql_result = Database::query($sql);
         $group_available_place = array ();
diff --git a/main/tracking/courseLog.php b/main/tracking/courseLog.php
index 578784748e..75c6962758 100644
--- a/main/tracking/courseLog.php
+++ b/main/tracking/courseLog.php
@@ -708,4 +708,4 @@ if ($_GET['studentlist'] == 'false') {
     $table->display();
 }
 
-Display::display_footer();
+Display::display_footer();
\ No newline at end of file
diff --git a/main/work/work.php b/main/work/work.php
index e054e3afcf..08d63b3e7f 100644
--- a/main/work/work.php
+++ b/main/work/work.php
@@ -188,7 +188,7 @@ if (!empty($group_id)) {
         $show_work = true;
     } else {
         // you are not a teacher              
-        $show_work = GroupManager::user_has_access($user_id, $group_id, GROUP_TOOL_WORK);
+        $show_work = GroupManager::user_has_access($user_id, $group_id, GroupManager::GROUP_TOOL_WORK);
     }
     
     if (!$show_work) {