diff --git a/js/ui/extensionSystem.js b/js/ui/extensionSystem.js
index 4e9ebb0f7..860f5fbc3 100644
--- a/js/ui/extensionSystem.js
+++ b/js/ui/extensionSystem.js
@@ -74,7 +74,7 @@ var ExtensionManager = class {
     }
 
     _extensionSupportsSessionMode(uuid) {
-        let extension = this.lookup(uuid);
+        const extension = this.lookup(uuid);
 
         if (!extension)
             return false;
diff --git a/js/ui/sessionMode.js b/js/ui/sessionMode.js
index afcd67cfd..7629a509b 100644
--- a/js/ui/sessionMode.js
+++ b/js/ui/sessionMode.js
@@ -42,6 +42,7 @@ const _modes = {
     },
 
     'gdm': {
+        allowExtensions: true,
         hasNotifications: true,
         isGreeter: true,
         isPrimary: true,
@@ -58,6 +59,7 @@ const _modes = {
     },
 
     'unlock-dialog': {
+        allowExtensions: true,
         isLocked: true,
         unlockDialog: undefined,
         components: ['polkitAgent', 'telepathyClient'],