Merge pull request #1863 from kainhofer/MultiOrgMemberHandling

Fix crash when adding member from different org (navigation URL stack was accessed with non-existing index)

Author: Fasse

src/Application/Navigation.php

@@ -170,7 +170,11 @@ public function getStack(): array
      */
     public function getStackEntryUrl(int $index): string
     {
-        return $this->urlStack[$index]['url'];
+        if (isset($this->urlStack[$index])) {
+            return $this->urlStack[$index]['url'];
+        } else {
+            return '';
+        }
     }
 
     /**