diff --git a/tree-view-sample/README.md b/tree-view-sample/README.md
index 00c77bed..3eadaa89 100644
--- a/tree-view-sample/README.md
+++ b/tree-view-sample/README.md
@@ -6,7 +6,7 @@
 
 ## Running the example
 
-- Open this example in VS Code
+- Open this example in VS Code Insiders
 - `npm install`
 - `npm run compile`
 - `F5` to start debugging
diff --git a/tree-view-sample/package.json b/tree-view-sample/package.json
index 79915c9e..741fcd40 100644
--- a/tree-view-sample/package.json
+++ b/tree-view-sample/package.json
@@ -7,6 +7,7 @@
 	"engines": {
 		"vscode": "^1.20.0"
 	},
+	"enableProposedApi": true,
 	"categories": [
 		"Other"
 	],
diff --git a/tree-view-sample/vscode.proposed.d.ts b/tree-view-sample/vscode.proposed.d.ts
index 0086481a..b6f93ca0 100644
--- a/tree-view-sample/vscode.proposed.d.ts
+++ b/tree-view-sample/vscode.proposed.d.ts
@@ -639,3 +639,4 @@ declare module 'vscode' {
 		getParent?(element: T): ProviderResult<T>;
 
 	}
+}
\ No newline at end of file