diff --git a/application/utils.inc.php b/application/utils.inc.php
index f881ef0be7..de9425d576 100644
--- a/application/utils.inc.php
+++ b/application/utils.inc.php
@@ -2662,7 +2662,7 @@ class utils
 				}
 
 				// Note: Endpoints are defaults only and should be overloaded by other GUIs such as the end-users portal
-				$sMentionEndpoint = utils::GetAbsoluteUrlAppRoot().'pages/ajax.render.php?operation=cke_mentions&marker='.$sMentionMarker.'&needle={encodedQuery}';
+				$sMentionEndpoint = utils::GetAbsoluteUrlAppRoot().'pages/ajax.render.php?operation=cke_mentions&marker='.urlencode($sMentionMarker).'&needle={encodedQuery}';
 				$sMentionItemUrl = utils::GetAbsoluteUrlAppRoot().'pages/UI.php?operation=details&class='.$sMentionClass.'&id={id}';
 
 				$sMentionItemPictureTemplate = (empty(MetaModel::GetImageAttributeCode($sMentionClass))) ? '' : <<<HTML