src/vs/platform/list/browser/listService.ts/MultipleSelectionController/isSelectionSingleChangeEvent
class MultipleSelectionController:	isSelectionSingleChangeEvent(event: IListMouseEvent<T> | IListTouchEvent<T>): boolean {
		if (this.useAltAsMultipleSelectionModifier) {
			return event.browserEvent.altKey;
		}

		return isSelectionSingleChangeEvent(event);
	}