Issue 3801 - Add pre-configurable preference for additional subscriptions

options.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 654 matching lines @@
   var removeButton = element.getElementsByClassName("subscriptionRemoveButton")[0];
   removeButton.setAttribute("title", removeButton.textContent);
   removeButton.textContent = "\xD7";
   removeButton.addEventListener("click", function()
   {
     if (!confirm(i18n.getMessage("global_remove_subscription_warning")))
       return;
 
     FilterStorage.removeSubscription(subscription);
   }, false);
+  if (Prefs.additional_subscriptions.indexOf(subscription.url) != -1)
+    removeButton.style.visibility = "hidden";
 
   var enabled = element.getElementsByClassName("subscriptionEnabled")[0];
   enabled.addEventListener("click", function()
   {
     if (subscription.disabled == !enabled.checked)
       return;
 
     subscription.disabled = !enabled.checked;
   }, false);
 
@@ skipping 16 matching lines @@
       links[i].href = arguments[i + 1];
       links[i].setAttribute("target", "_blank");
     }
     else if (typeof arguments[i + 1] == "function")
     {
       links[i].href = "javascript:void(0);";
       links[i].addEventListener("click", arguments[i + 1], false);
     }
   }
 }