* Added ability to interrupt a kernel to FrontendWidget

* Fixed bug where 'Cut' operation was permitted with keyboard shortcut
* Fixed usability issue: calltips are now closed when Enter is pressed

IPython/frontend/qt/console/call_tip_widget.py

@@ -11,7 +11,7 b' class CallTipWidget(QtGui.QLabel):'
     """
 
     #--------------------------------------------------------------------------
-    # 'QWidget' interface
+    # 'QObject' interface
     #--------------------------------------------------------------------------
 
     def __init__(self, parent):
@@ -34,12 +34,23 b' class CallTipWidget(QtGui.QLabel):'
         self.setWindowOpacity(self.style().styleHint(
                 QtGui.QStyle.SH_ToolTipLabel_Opacity, None, self) / 255.0)
 
+    #--------------------------------------------------------------------------
+    # 'QWidget' interface
+    #--------------------------------------------------------------------------
+
     def hideEvent(self, event):
         """ Reimplemented to disconnect the cursor movement handler.
         """
         QtGui.QLabel.hideEvent(self, event)
         self.parent().cursorPositionChanged.disconnect(self._update_tip)
 
+    def keyPressEvent(self, event):
+        """ Reimplemented to hide on certain key presses.
+        """
+        if event.key() in (QtCore.Qt.Key_Enter, QtCore.Qt.Key_Return, 
+                           QtCore.Qt.Key_Escape):
+            self.hide()
+
     def paintEvent(self, event):
         """ Reimplemented to paint the background panel.
         """

IPython/frontend/qt/console/console_widget.py

@@ -123,6 +123,8 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
                          QtCore.Qt.Key_P : QtCore.Qt.Key_Up,
                          QtCore.Qt.Key_N : QtCore.Qt.Key_Down,
                          QtCore.Qt.Key_D : QtCore.Qt.Key_Delete, }
+    _shortcuts = set(_ctrl_down_remap.keys() +
+                     [ QtCore.Qt.Key_C, QtCore.Qt.Key_V ])
 
     #---------------------------------------------------------------------------
     # 'QObject' interface
@@ -170,7 +172,7 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
                 sys.platform != 'darwin' and \
                 event.type() == QtCore.QEvent.ShortcutOverride and \
                 self._control_down(event.modifiers()) and \
-                event.key() in self._ctrl_down_remap:
+                event.key() in self._shortcuts:
             event.accept()
             return True
         else:
@@ -220,6 +222,9 b' class ConsoleWidget(QtGui.QPlainTextEdit):'
                     cursor.removeSelectedText()
                 intercepted = True
 
+            elif key == QtCore.Qt.Key_X:
+                intercepted = True
+
             elif key == QtCore.Qt.Key_Y:
                 self.paste()
                 intercepted = True

IPython/frontend/qt/console/frontend_widget.py

@@ -1,3 +1,6 b''
+# Standard library imports
+import signal
+
 # System library imports
 from pygments.lexers import PythonLexer
 from PyQt4 import QtCore, QtGui
@@ -77,14 +80,18 b' class FrontendWidget(HistoryConsoleWidget):'
         """ Reimplemented to hide calltips.
         """
         self._call_tip_widget.hide()
-        return super(FrontendWidget, self).focusOutEvent(event)
+        super(FrontendWidget, self).focusOutEvent(event)
 
     def keyPressEvent(self, event):
-        """ Reimplemented to hide calltips.
+        """ Reimplemented to allow calltips to process events and to send
+            signals to the kernel.
         """
-        if event.key() == QtCore.Qt.Key_Escape:
-            self._call_tip_widget.hide()
-        return super(FrontendWidget, self).keyPressEvent(event)
+        if self._executing and event.key() == QtCore.Qt.Key_C and \
+                self._control_down(event.modifiers()):
+            self._interrupt_kernel()
+        else:
+            self._call_tip_widget.keyPressEvent(event)
+            super(FrontendWidget, self).keyPressEvent(event)
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' abstract interface
@@ -168,6 +175,10 b' class FrontendWidget(HistoryConsoleWidget):'
             xreq.complete_reply.disconnect(self._handle_complete_reply)
             xreq.object_info_reply.disconnect(self._handle_object_info_reply)
 
+            # Handle the case where the old kernel manager is still listening.
+            if self._kernel_manager.is_listening:
+                self._stopped_listening()
+
         # Set the new kernel manager.
         self._kernel_manager = kernel_manager
         if kernel_manager is None:
@@ -240,6 +251,15 b' class FrontendWidget(HistoryConsoleWidget):'
         text = unicode(cursor.selectedText())
         return self._completion_lexer.get_context(text)
 
+    def _interrupt_kernel(self):
+        """ Attempts to the interrupt the kernel.
+        """
+        if self.kernel_manager.has_kernel:
+            self.kernel_manager.signal_kernel(signal.SIGINT)
+        else:
+            self.appendPlainText('Kernel process is either remote or '
+                                 'unspecified. Cannot interrupt.\n')
+
     #------ Signal handlers ----------------------------------------------------
 
     def _document_contents_change(self, position, removed, added):