title: Open custom page on the settings click, firefox addon SDK
body: <p>I'm using Firefox addon-SDK to create my addon.
  I use <a href="https://addons.mozilla.org/en-US/developers/docs/sdk/latest/modules/sdk/simple-prefs.html" rel="nofollow">simple-prefs</a> for the options, but how can I open <em>custom</em> page when user clicks on the "Settings" button in the Firefox addon manager?<br>
  Thank you for any help!</p>