message: Fix `remove-label-faster`
diff: @@ -4,7 +4,7 @@ import XIcon from 'octicon/x.svg';
  import select from 'select-dom';
  import oneTime from 'onetime';
  import delegate from 'delegate-it';
  -import {observe} from 'selector-observer';
  +import {observe, Observer} from 'selector-observer';
  import * as pageDetect from 'github-url-detection';
  import features from '.';
  @@ -12,6 +12,7 @@ import * as api from '../github-helpers/api';
  import {getRepoURL, getConversationNumber} from '../github-helpers';
  +let observer: Observer;
  const canNotEditLabels = oneTime((): boolean => !select.exists('.sidebar-labels .octicon-gear'));
  async function removeLabelButtonClickHandler(event: delegate.Event<MouseEvent, HTMLButtonElement>): Promise<void> {
  @@ -56,7 +57,7 @@ function makeRemoveLabelButton(labelName: string, backgroundColor: string) {
  async function init(): Promise<void> {
  await api.expectToken();
  - observe('.labels > a:not(.rgh-remove-label-faster-already-added)', {
  + observer = observe('.labels > a:not(.rgh-remove-label-faster-already-added)', {
  constructor: HTMLElement,
  add(label) {
  label.classList.add('rgh-remove-label-faster-already-added');
  @@ -67,6 +68,10 @@ async function init(): Promise<void> {
  delegate(document, '.rgh-remove-label-faster:not([disabled])', 'click', removeLabelButtonClickHandler);
  }
  +function deinit() {
  + observer.abort();
  +}
  +
  void features.add({
  id: __filebasename,
  description: 'Adds one-click buttons to remove labels in conversations.',
  @@ -79,5 +84,6 @@ void features.add({
  exclude: [
  canNotEditLabels
  ],
  - init: oneTime(init)
  + init,
  + deinit
  });
  