diff --git a/src/applications/dashboard/layoutconfig/PhabricatorDashboardPanelRefList.php b/src/applications/dashboard/layoutconfig/PhabricatorDashboardPanelRefList.php
index 7135522840..3d9b7d83ed 100644
--- a/src/applications/dashboard/layoutconfig/PhabricatorDashboardPanelRefList.php
+++ b/src/applications/dashboard/layoutconfig/PhabricatorDashboardPanelRefList.php
@@ -13,7 +13,7 @@ final class PhabricatorDashboardPanelRefList
 
     $mode_map = PhabricatorDashboardLayoutMode::getAllLayoutModes();
     $mode_key = idx($config, 'layoutMode');
-    if (!isset($mode_map[$mode_key])) {
+    if ($mode_key === null || !isset($mode_map[$mode_key])) {
       $mode_key = head_key($mode_map);
     }
     $mode = $mode_map[$mode_key];