src/vs/workbench/api/common/extHostQuickOpen.ts/ExtHostQuickPick/selectedItems
class ExtHostQuickPick:		set selectedItems(selectedItems: T[]) {
			this._selectedItems = selectedItems.filter(item => this._itemsToHandles.has(item));
			this.update({ selectedItems: this._selectedItems.map(item => this._itemsToHandles.get(item)) });
		}