Make test for using Pale Moon workaround stricter.

src/General/lib/$.coffee

@@ -226,23 +226,24 @@ $.event = (event, detail, root=d) ->
 
 <% if (type === 'userscript') { %>
 # XXX Make $.event work in Pale Moon with GM 3.x (no cloneInto function).
-unless typeof cloneInto is 'function' or /^[01]\./.test(GM_info.version) or GM_info.scriptHandler # not FF30+, GM1-, or Tampermonkey
-  do ->
-    try
-      new CustomEvent 'x', detail: {}
-    catch err
-      unsafeConstructors =
-        Object: unsafeWindow.Object
-        Array:  unsafeWindow.Array
-      clone = (obj) ->
-        if obj? and typeof obj is 'object' and (constructor = unsafeConstructors[obj.constructor.name])
-          obj2 = new constructor()
-          obj2[key] = clone val for key, val of obj
-          obj2
-        else
-          obj
-      $.event = (event, detail, root=d) ->
-        root.dispatchEvent new CustomEvent event, {bubbles: true, detail: clone detail}
+do ->
+  return unless /PaleMoon\//.test(navigator.userAgent) and +GM_info?.version?.split('.')[0] >= 2 and typeof cloneInto is 'undefined'
+
+  try
+    new CustomEvent 'x', detail: {}
+  catch err
+    unsafeConstructors =
+      Object: unsafeWindow.Object
+      Array:  unsafeWindow.Array
+    clone = (obj) ->
+      if obj? and typeof obj is 'object' and (constructor = unsafeConstructors[obj.constructor.name])
+        obj2 = new constructor()
+        obj2[key] = clone val for key, val of obj
+        obj2
+      else
+        obj
+    $.event = (event, detail, root=d) ->
+      root.dispatchEvent new CustomEvent event, {bubbles: true, detail: clone detail}
 <% } %>
 
 $.open =