From 07e70148dacb8cd84f976f796320c9f47c33b3a0 Mon Sep 17 00:00:00 2001
From: Chris Joe <flamerohr@users.noreply.github.com>
Date: Wed, 31 Jan 2018 10:45:31 +1300
Subject: [PATCH] BUG Add some exist check for tabsets which may not be there
 (#2079)

---
 code/Model/SiteTreeFileFormFactoryExtension.php | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/code/Model/SiteTreeFileFormFactoryExtension.php b/code/Model/SiteTreeFileFormFactoryExtension.php
index 4b8a9f77..c3d6583a 100644
--- a/code/Model/SiteTreeFileFormFactoryExtension.php
+++ b/code/Model/SiteTreeFileFormFactoryExtension.php
@@ -37,10 +37,13 @@ class SiteTreeFileFormFactoryExtension extends DataExtension
             $usedOnField->setDescription($backlinkHTML);
         }
 
-        // Add field to new tab
-        $tab = Tab::create('Usage', _t(__CLASS__.'.USAGE', 'Usage'), $usedOnField);
         /** @var TabSet $tabset */
         $tabset = $fields->fieldByName('Editor');
-        $tabset->push($tab);
+        if ($tabset) {
+            // Add field to new tab
+            /** @var Tab $tab */
+            $tab = Tab::create('Usage', _t(__CLASS__.'.USAGE', 'Usage'), $usedOnField);
+            $tabset->push($tab);
+        }
     }
 }