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 (!AppOptions.get("pdfBugEnabled")) {
      return;
    }
    const hash = document.location.hash.substring(1);
    if (!hash) {
      return;
    }
    const params = parseQueryString(hash),
      waitOn = [];
    if (params.get("disableworker") === "true") {
      waitOn.push(loadFakeWorker());
    }
    if (params.has("disablerange")) {
      AppOptions.set("disableRange", params.get("disablerange") === "true");
    }
    if (params.has("disablestream")) {