Since #12241 we have notifications for this when the user navigates away from the viewer, but we do not yet warn when switching documents, which means that if you call e.g. `PDFViewerApplication.open` with a new document (or directly call `BaseViewer.setDocument` when using the viewer components standalone) there won't be any warning about losing form data. This should be addressed.
if (darkRules?.[1]) {
            styleSheet.deleteRule(i);
            styleSheet.insertRule(darkRules[1], i);
          }
          return;
        }
      }
    } catch (reason) {
      console.error(`_forceCssTheme: "${reason?.message}".`);
    }
  },
  /**
   * @private
   */
  async _initializeViewerComponents() {
    const appConfig = this.appConfig;
    const eventBus =
      appConfig.eventBus ||
      new EventBus({ isInAutomation: this.externalServices.isInAutomation });
    this.eventBus = eventBus;
    this.overlayManager = new OverlayManager();
    const pdfRenderingQueue = new PDFRenderingQueue();
    pdfRenderingQueue.onIdle = this.cleanup.bind(this);
    this.pdfRenderingQueue = pdfRenderingQueue;
    const pdfLinkService = new PDFLinkService({
      eventBus,
      externalLinkTarget: AppOptions.get("externalLinkTarget"),
      externalLinkRel: AppOptions.get("externalLinkRel"),
      ignoreDestinationZoom: AppOptions.get("ignoreDestinationZoom"),
    });