URL resource FAQ
From MoodleDocs
Why can't I get my URL to open in a new window?
The default settings for displaying a URL resource are: Automatic, Embed, Open or Popup. However, there are other display options too which the site admin can select from Settings>Site Administration>Plugins>Activity Modules>URL If you don't have the option to display your URL in a new window, check this setting has been enabled.
