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 (stored.page && viewOnLoad !== ViewOnLoad.INITIAL) {
            hash =
              `page=${stored.page}&zoom=${zoom || stored.zoom},` +
              `${stored.scrollLeft},${stored.scrollTop}`;
            rotation = parseInt(stored.rotation, 10);
            
            if (sidebarView === SidebarView.UNKNOWN) {
              sidebarView = stored.sidebarView | 0;
            }
            if (scrollMode === ScrollMode.UNKNOWN) {
              scrollMode = stored.scrollMode | 0;
            }
            if (spreadMode === SpreadMode.UNKNOWN) {
              spreadMode = stored.spreadMode | 0;
            }
          }
          
          if (pageMode && sidebarView === SidebarView.UNKNOWN) {
            sidebarView = apiPageModeToSidebarView(pageMode);
          }
          if (pageLayout && spreadMode === SpreadMode.UNKNOWN) {
            spreadMode = apiPageLayoutToSpreadMode(pageLayout);
          }
          this.setInitialView(hash, {
            rotation,
            sidebarView,
            scrollMode,
            spreadMode,
          });
          this.eventBus.dispatch("documentinit", { source: this });