diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index cf0218df999bceb3b73c958814eae132059d2a63..a8877a7c25cff6475bbb74ccc91e70431896f640 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -71,7 +71,6 @@ declare module 'vscode' {
 
 		/**
 		 * Collapsible state of the tree item.
-		 * Required only when item has children.
 		 */
 		readonly collapsibleState?: TreeItemCollapsibleState;
 	}
@@ -80,6 +79,10 @@ declare module 'vscode' {
 	 * Collapsible state of the tree item
 	 */
 	export enum TreeItemCollapsibleState {
+		/**
+		 * Determines an item can be neither collapsed nor expanded. Implies it has no children.
+		 */
+		None = 0,
 		/**
 		 * Determines an item is collapsed
 		 */
diff --git a/src/vs/workbench/parts/views/browser/views.ts b/src/vs/workbench/parts/views/browser/views.ts
index 927059f19775738501836cb16e9eed258a45f4b9..d313003efc2a8dd6759cdfb500a6dacc72290d56 100644
--- a/src/vs/workbench/parts/views/browser/views.ts
+++ b/src/vs/workbench/parts/views/browser/views.ts
@@ -21,6 +21,7 @@ export class ViewLocation {
 }
 
 export enum TreeItemCollapsibleState {
+	None = 0,
 	Collapsed = 1,
 	Expanded = 2
 }
@@ -48,7 +49,7 @@ export interface IViewDescriptor {
 	readonly ctor: IViewConstructorSignature;
 
 	readonly order?: number;
-
+	
 }
 
 export interface ITreeItem {