Worked around Fennec bug: selecting a subscription in the list is ignored

lib/ui.js

Index: lib/ui.js
===================================================================
--- a/lib/ui.js
+++ b/lib/ui.js
@@ -186,21 +186,31 @@ let optionsObserver =
 
             if (currentSubscription && list.selectedIndex < 0)
             {
               list.appendItem(currentSubscription.title, currentSubscription.url, null);
               list.selectedIndex = list.itemCount - 1;
             }
           }
 
-          list.addEventListener("command", function(event)
+          var listener = function()
           {
             if (list.value)
               UI.setSubscription(list.value, list.label);
-          }, false);
+          }
+          list.addEventListener("command", listener, false);
+
+          // xul:menulist in Fennec is broken and doesn't trigger any events
+          // on selection. Have to detect selectIndex changes instead.
+          // See http://hg.mozilla.org/mozilla-central/file/04d8c309fe72/mobile/android/chrome/content/SelectHelper.js#l40
+          list.watch("selectedIndex", function(prop, oldval, newval)
+          {
+            Utils.runAsync(listener);
+            return newval;
+          });
         }, false);
         request.send();
       }
     }
   },
 
   observe: function(subject, topic, data)
   {