diff --git a/polygerrit-ui/app/elements/edit/gr-default-editor/gr-default-editor.js b/polygerrit-ui/app/elements/edit/gr-default-editor/gr-default-editor.js
index bae838ef98..ed96bb23eb 100644
--- a/polygerrit-ui/app/elements/edit/gr-default-editor/gr-default-editor.js
+++ b/polygerrit-ui/app/elements/edit/gr-default-editor/gr-default-editor.js
@@ -19,7 +19,6 @@
 
   Polymer({
     is: 'gr-default-editor',
-    _legacyUndefinedCheck: true,
 
     /**
      * Fired when the content of the editor changes.
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.js b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.js
index 35b78ca161..ca678a5b51 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.js
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.js
@@ -19,7 +19,7 @@
 
   Polymer({
     is: 'gr-edit-controls',
-    _legacyUndefinedCheck: true,
+
     properties: {
       change: Object,
       patchNum: String,
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-file-controls/gr-edit-file-controls.js b/polygerrit-ui/app/elements/edit/gr-edit-file-controls/gr-edit-file-controls.js
index 9c59a9a8da..250816b970 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-file-controls/gr-edit-file-controls.js
+++ b/polygerrit-ui/app/elements/edit/gr-edit-file-controls/gr-edit-file-controls.js
@@ -19,7 +19,6 @@
 
   Polymer({
     is: 'gr-edit-file-controls',
-    _legacyUndefinedCheck: true,
 
     /**
      * Fired when an action in the overflow menu is tapped.
diff --git a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.js b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.js
index 08dcf51ca3..95cfaf6bab 100644
--- a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.js
+++ b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.js
@@ -26,7 +26,6 @@
 
   Polymer({
     is: 'gr-editor-view',
-    _legacyUndefinedCheck: true,
 
     /**
      * Fired when the title of the page should change.