fixes #25354

src/vs/base/parts/tree/browser/treeView.ts

@@ -23,6 +23,7 @@ import { HeightMap, IViewItem } from 'vs/base/parts/tree/browser/treeViewModel';
 import _ = require('vs/base/parts/tree/browser/tree');
 import { KeyCode } from 'vs/base/common/keyCodes';
 import Event, { Emitter } from 'vs/base/common/event';
+import { IDomNodePagePosition } from 'vs/base/browser/dom';
 
 export interface IRow {
 	element: HTMLElement;
@@ -1220,14 +1221,17 @@ export class TreeView extends HeightMap {
 			var keyboardEvent = new Keyboard.StandardKeyboardEvent(<KeyboardEvent>event);
 			element = this.model.getFocus();
 
+			var position: IDomNodePagePosition;
+
 			if (!element) {
-				return;
+				element = this.model.getInput();
+				position = DOM.getDomNodePagePosition(this.inputItem.element);
+			} else {
+				var id = this.context.dataSource.getId(this.context.tree, element);
+				var viewItem = this.items[id];
+				position = DOM.getDomNodePagePosition(viewItem.element);
 			}
 
-			var id = this.context.dataSource.getId(this.context.tree, element);
-			var viewItem = this.items[id];
-			var position = DOM.getDomNodePagePosition(viewItem.element);
-
 			resultEvent = new _.KeyboardContextMenuEvent(position.left + position.width, position.top, keyboardEvent);
 
 		} else {