3.3.3

   * Support Firefox versions after the [bug 1565170](https://bugzilla.mozilla.org/show_bug.cgi?id=1565170) is fixed.
   * Fix confused tab focus after some tabs are hidden and shown.
   * Don't expand locked-collapsed tree with a long press of the Ctrl key while Ctrl-Tab/Ctrl-Shift-Tab tab switching is in progress.
   * Allow to expand locked-collapsed tree when a descendant tab gets focus directly.
   * Hide options and other tab contents until they are initialized.