1.2.0

   * Add ability to set an accesskey for each format with the `&` mark in the label.
   * Add ability to set custom keyboard shortcut for each format.
   * Show format choosed dialog as a semi-modal popup window.

1.1.1

   * Don't show top level context menu items when extra context menu items are globally hidden.
   * Show formats correctly even if they are not migrated yet.
   * Restore default formats correctly.
   * Drop support for Firefox 63 and older versions.

1.1.0

   * Introduce "Enabled" checkbox for each format to hide it without deletion.
   * Show menu item directly in the context menu when only one item is available.

1.0.9

   * Show in-content confirmation dialog correctly on lately versions of Firefox.
   * Remove keyboard shorctut customization UI, because Firefox ESR68 has it.
   * Uninitialized options page is now invisible.

1.0.8: i.0.8

Correct dynamic update of context menu items on user interactions in the options page.

1.0.7

Remove obsolete codes deprecated at Firefox 70.