* The Qt console frontend now ignores cross chatter from other frontends.

* Fixed parent headers missing from OutStreams in both kernels.

IPython/frontend/qt/base_frontend_mixin.py

@@ -73,13 +73,21 b' class BaseFrontendMixin(object):'
         """
 
     #---------------------------------------------------------------------------
-    # Private interface
+    # 'BaseFrontendMixin' protected interface
     #---------------------------------------------------------------------------
 
     def _dispatch(self, msg):
-        """ Call the frontend handler associated with
+        """ Calls the frontend handler associated with the message type of the 
+            given message.
         """
         msg_type = msg['msg_type']
         handler = getattr(self, '_handle_' + msg_type, None)
         if handler:
             handler(msg)
+
+    def _is_from_this_session(self, msg):
+        """ Returns whether a reply from the kernel originated from a request
+            from this frontend.
+        """
+        session = self._kernel_manager.session.session
+        return msg['parent_header']['session'] == session

IPython/frontend/qt/console/frontend_widget.py

@@ -83,7 +83,7 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
         # FrontendWidget protected variables.
         self._call_tip_widget = CallTipWidget(self._control)
         self._completion_lexer = CompletionLexer(PythonLexer())
-        self._hidden = True
+        self._hidden = False
         self._highlighter = self._highlighter_class(self)
         self._input_splitter = self._input_splitter_class(input_mode='replace')
         self._kernel_manager = None
@@ -187,7 +187,6 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
             elif status == 'abort':
                 self._process_execute_abort(msg)
 
-            self._hidden = True
             self._show_interpreter_prompt_for_reply(msg)
             self.executed.emit(msg)
 
@@ -218,13 +217,15 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
     def _handle_pyout(self, msg):
         """ Handle display hook output.
         """
-        self._append_plain_text(msg['content']['data'] + '\n')
+        if not self._hidden and self._is_from_this_session(msg):
+            self._append_plain_text(msg['content']['data'] + '\n')
 
     def _handle_stream(self, msg):
         """ Handle stdout, stderr, and stdin.
         """
-        self._append_plain_text(msg['content']['data'])
-        self._control.moveCursor(QtGui.QTextCursor.End)
+        if not self._hidden and self._is_from_this_session(msg):
+            self._append_plain_text(msg['content']['data'])
+            self._control.moveCursor(QtGui.QTextCursor.End)
     
     def _started_channels(self):
         """ Called when the KernelManager channels have started listening or 

IPython/frontend/qt/console/ipython_widget.py

@@ -75,11 +75,13 b' class IPythonWidget(FrontendWidget):'
     def _handle_pyout(self, msg):
         """ Reimplemented for IPython-style "display hook".
         """
-        content = msg['content']
-        prompt_number = content['prompt_number']
-        self._append_plain_text(content['output_sep'])
-        self._append_html(self._make_out_prompt(prompt_number))
-        self._append_plain_text(content['data'] + '\n' + content['output_sep2'])
+        if not self._hidden and self._is_from_this_session(msg):
+            content = msg['content']
+            prompt_number = content['prompt_number']
+            self._append_plain_text(content['output_sep'])
+            self._append_html(self._make_out_prompt(prompt_number))
+            self._append_plain_text(content['data'] + '\n' + 
+                                    content['output_sep2'])
 
     #---------------------------------------------------------------------------
     # 'FrontendWidget' interface

IPython/zmq/ipkernel.py

@@ -152,8 +152,10 b' class Kernel(Configurable):'
             raw_input = lambda prompt='': self._raw_input(prompt, ident, parent)
             __builtin__.raw_input = raw_input
 
-            # Set the parent message of the display hook.
+            # Set the parent message of the display hook and out streams.
             self.shell.displayhook.set_parent(parent)
+            sys.stdout.set_parent(parent)
+            sys.stderr.set_parent(parent)
 
             self.shell.runlines(code)
         except:

IPython/zmq/pykernel.py

@@ -97,8 +97,10 b' class Kernel(HasTraits):'
             raw_input = lambda prompt='': self._raw_input(prompt, ident, parent)
             __builtin__.raw_input = raw_input
 
-            # Configure the display hook.
+            # Set the parent message of the display hook and out streams.
             sys.displayhook.set_parent(parent)
+            sys.stdout.set_parent(parent)
+            sys.stderr.set_parent(parent)
 
             exec comp_code in self.user_ns, self.user_ns
         except: