diff --git a/libpathod/app.py b/libpathod/app.py
index 38d0be33a..e073921cb 100644
--- a/libpathod/app.py
+++ b/libpathod/app.py
@@ -108,7 +108,6 @@ def _preview(is_request):
         section = "main",
         syntaxerror = None,
         error = None,
-        pauses = None
     )
     if not spec.strip():
         args["error"] = "Can't parse an empty spec."
@@ -125,16 +124,16 @@ def _preview(is_request):
         return render(template, False, **args)
 
     s = cStringIO.StringIO()
-    args["pauses"] = r.preview_safe()
+    safe = r.preview_safe()
 
-    c = app.config["pathod"].check_policy(r, app.config["pathod"].request_settings)
+    c = app.config["pathod"].check_policy(safe, app.config["pathod"].request_settings)
     if c:
         args["error"] = c
         return render(template, False, **args)
     if is_request:
-        r.serve(s, app.config["pathod"].request_settings, host="example.com")
+        safe.serve(s, app.config["pathod"].request_settings, host="example.com")
     else:
-        r.serve(s, app.config["pathod"].request_settings)
+        safe.serve(s, app.config["pathod"].request_settings)
 
     args["output"] = utils.escape_unprintables(s.getvalue())
     return render(template, False, **args)
diff --git a/libpathod/language.py b/libpathod/language.py
index f7909b81f..ba462abe0 100644
--- a/libpathod/language.py
+++ b/libpathod/language.py
@@ -167,7 +167,7 @@ class FileGenerator:
 
 class _Token(object):
     """
-        A specification token.
+        A specification token. Tokens are immutable.
     """
     __metaclass__ = abc.ABCMeta
     @abc.abstractmethod
@@ -646,11 +646,10 @@ class _Message(object):
 
     def preview_safe(self):
         """
-            Modify this message to be safe for previews. Returns a list of elided actions.
+            Return a copy of this message that issafe for previews.
         """
-        pauses = [i for i in self.actions if isinstance(i, PauseAt)]
-        #self.actions = [i for i in self.actions if not isinstance(i, PauseAt)]
-        return pauses
+        tokens = [i for i in self.tokens if not isinstance(i, PauseAt)]
+        return self.__class__(tokens)
 
     def maximum_length(self, settings, request_host):
         """
diff --git a/libpathod/templates/request_preview.html b/libpathod/templates/request_preview.html
index e4efd9d01..db08580e6 100644
--- a/libpathod/templates/request_preview.html
+++ b/libpathod/templates/request_preview.html
@@ -40,9 +40,7 @@
         </div>
         <div class="span10">
             <pre>{{ output }}</pre>
-            {% if pauses %}
-                <p>Note: pauses are skipped when generating previews!</p>
-            {% endif %}  
+            <p>Note: pauses are skipped when generating previews!</p>
         </div>
     </div>
 {% endif %}  
diff --git a/libpathod/templates/response_preview.html b/libpathod/templates/response_preview.html
index c725bcf8c..bb72513d4 100644
--- a/libpathod/templates/response_preview.html
+++ b/libpathod/templates/response_preview.html
@@ -40,9 +40,7 @@
         </div>
         <div class="span10">
             <pre>{{ output }}</pre>
-            {% if pauses %}
-                <p>Note: pauses are skipped when generating previews!</p>
-            {% endif %}  
+            <p>Note: pauses are skipped when generating previews!</p>
         </div>
     </div>
 {% endif %}  
diff --git a/test/test_language.py b/test/test_language.py
index 6d9fa31d8..d0f431986 100644
--- a/test/test_language.py
+++ b/test/test_language.py
@@ -606,9 +606,9 @@ class TestResponse:
 
     def test_render(self):
         r = language.parse_response({}, "400:p0,100:dr")
-        assert r.actions[0].spec() == "p0,100"
-        assert len(r.preview_safe()) == 1
-        assert not r.actions[0].spec().startswith("p")
+        assert "p0" in r.spec()
+        s = r.preview_safe()
+        assert not "p0" in s.spec()