Fix PHP,warnings

main/dropbox/index.php

@@ -75,7 +75,8 @@ if ($action == 'addreceivedcategory' || $action == 'addsentcategory') {
 	if (api_get_session_id() != 0 && !api_is_allowed_to_session_edit(false, true)) {
 		api_not_allowed();
 	}
-	display_addcategory_form($_POST['category_name'], '', $_GET['action']);
+	$categoryName = isset($_POST['category_name']) ? $_POST['category_name'] : '';
+	display_addcategory_form($categoryName, '', $_GET['action']);
 }
 
 // Editing a category: displaying the form

main/inc/lib/usergroup.lib.php

@@ -1345,7 +1345,11 @@ class UserGroup extends Model
         $form->setRequiredNote('<span class="form_required">*</span> <small>'.get_lang('ThisFieldIsRequired').'</small>');
 
         // Setting the form elements
-        $form->addButtonCreate($header);
+        if ($type == 'add') {
+            $form->addButtonCreate($header);
+        } else {
+            $form->addButtonUpdate($header);
+        }
     }
 
     /**

main/social/groups.php

@@ -15,6 +15,7 @@ api_block_anonymous_users();
 if (api_get_setting('allow_social_tool') !='true') {
     api_not_allowed();
 }
+$join_url = '';
 
 $this_section = SECTION_SOCIAL;
 $allowed_views = array('mygroups','newest','pop');