* ConsoleWidget no longer stores contiguous identical lines

* FrontendWidget now prints to the terminal rather than itself when it receives an unknown payload.

IPython/frontend/qt/console/console_widget.py

@@ -1496,11 +1496,14 b' class HistoryConsoleWidget(ConsoleWidget):'
             source, hidden, interactive)
 
         if executed and not hidden:
-            # Save the command unless it was a blank line.
+            # Save the command unless it was an empty string or was identical 
+            # to the previous command.
             history = history.rstrip()
-            if history:
+            if history and (not self._history or self._history[-1] != history):
                 self._history.append(history)
-                self._history_index = len(self._history)
+
+            # Move the history index to the most recent item.
+            self._history_index = len(self._history)
 
         return executed
 

IPython/frontend/qt/console/frontend_widget.py

@@ -10,6 +10,7 b' from PyQt4 import QtCore, QtGui'
 # Local imports
 from IPython.core.inputsplitter import InputSplitter
 from IPython.frontend.qt.base_frontend_mixin import BaseFrontendMixin
+from IPython.utils.io import raw_print
 from IPython.utils.traitlets import Bool
 from bracket_matcher import BracketMatcher
 from call_tip_widget import CallTipWidget
@@ -432,8 +433,8 b' class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):'
         payload = msg['content']['payload']
         for item in payload:
             if not self._process_execute_payload(item):
-                warning = 'Received unknown payload of type %s\n'
-                self._append_plain_text(warning % repr(item['source']))
+                warning = 'Warning: received unknown payload of type %s'
+                raw_print(warning % repr(item['source']))
 
     def _process_execute_payload(self, item):
         """ Process a single payload item from the list of payload items in an