diff --git a/localtypings/pxteditor.d.ts b/localtypings/pxteditor.d.ts
index 0364180fa5a..26dd274455a 100644
--- a/localtypings/pxteditor.d.ts
+++ b/localtypings/pxteditor.d.ts
@@ -1120,7 +1120,7 @@ declare namespace pxt.editor {
         blocklyToolbox: ToolboxDefinition;
         monacoToolbox: ToolboxDefinition;
         projectView: IProjectView;
-        showNotification: (msg) => void;
+        showNotification: (msg: string) => void;
     }
 
     export interface IToolboxOptions {