STR:
  - Go to https://mozilla.github.io/pdf.js/web/viewer.html
  - Click on "Open File" and open a pdf

The `Download` button and the `Current view` one just disappear.
I can reproduce this bug with Firefox nightly, Chrome stable and Epiphany on debian.
if (!this.isViewerEmbedded) {
            pdfViewer.focus();
          }
          
          
          this._initializePermissions(pdfDocument);
          
          
          
          
          
          await Promise.race([
            pagesPromise,
            new Promise(resolve => {
              setTimeout(resolve, FORCE_PAGES_LOADED_TIMEOUT);
            }),
          ]);
          if (!initialBookmark && !hash) {
            return;
          }
          if (pdfViewer.hasEqualPageSizes) {
            return;
          }
          this.initialBookmark = initialBookmark;
          
          pdfViewer.currentScaleValue = pdfViewer.currentScaleValue;
          
          this.setInitialView(hash);