diff --git a/src/Resources/contao/classes/FilterSession.php b/src/Resources/contao/classes/FilterSession.php
index abf91da..e60a224 100644
--- a/src/Resources/contao/classes/FilterSession.php
+++ b/src/Resources/contao/classes/FilterSession.php
@@ -360,7 +360,7 @@ public function getTypeParameterByGroups($arrGroups, $mode, $addFragments=true,
 
         $arrTypeColumns = array();
 
-        if(\count($arrGroups))
+        if(($arrGroups ?? null) && \count($arrGroups))
         {
             $objRealEstateTypes = RealEstateTypeModel::findPublishedByPids($arrGroups);