--- PyShell.py.orig	2008-05-04 17:30:43.000000000 -0500
+++ PyShell.py	2008-06-16 19:54:07.000000000 -0500
@@ -303,13 +303,18 @@
         })
 
 class ModifiedUndoDelegator(UndoDelegator):
-    "Extend base class: forbid insert/delete before the I/O mark"
-
+    "Extend base class: redirects insert/delete to the end mark"
+    
     def insert(self, index, chars, tags=None):
         try:
-            if self.delegate.compare(index, "<", "iomark"):
-                self.delegate.bell()
-                return
+            if self.delegate.compare(index, "<", "iomark"): 
+                try:            # improved behavior
+                    text = self.delegate.delegate.delegate      
+                    text.mark_set("insert", "end-1c")           
+                except:         # on error, default to old behavior
+                    self.delegate.bell()
+                    return
+
         except TclError:
             pass
         UndoDelegator.insert(self, index, chars, tags)
@@ -828,6 +833,12 @@
         text.bind("<<open-stack-viewer>>", self.open_stack_viewer)
         text.bind("<<toggle-debugger>>", self.toggle_debugger)
         text.bind("<<toggle-jit-stack-viewer>>", self.toggle_jit_stack_viewer)
+
+        text.bind("<<key-up-callback>>", self.key_up_callback);     
+        text.bind("<<key-down-callback>>", self.key_down_callback);   
+        text.event_add("<<key-up-callback>>", "<Key-Up>");         
+        text.event_add("<<key-down-callback>>", "<Key-Down>");       
+
         if use_subprocess:
             text.bind("<<view-restart>>", self.view_restart_mark)
             text.bind("<<restart-shell>>", self.restart_shell)
@@ -848,6 +859,89 @@
         #
         self.pollinterval = 50  # millisec
 
+
+    def history_ismember(self):
+        """ if the current input is in the history, return true """
+
+        # this function should be in IdleHistory.py - RDS
+        s = self.history._get_source('iomark', 'end-1c')
+        for i in self.history.history:
+            if i == s:
+                return True
+
+        return False
+
+    def key_up_callback(self, event):    
+
+        if self.text.compare('insert', '>=', 'iomark'):
+            # cursor inside current input
+            s = self.text.get('iomark', 'end-1c')
+
+            if s.find('\n') == -1:
+                # single line input
+
+                if self.text.compare('insert', '==', 'end-1c'):
+                    self.history.history_prev(event)
+                    return "break"
+                else:
+                    self.text.mark_set('insert', 'end-1c')
+                    return "break"
+
+            else:
+                # multiline input
+
+                if self.text.compare('insert linestart-1c', '==', \
+                   'iomark lineend'):
+                    # correction in cursor placement due to ">>>"
+                    line,column = self.text.index(INSERT).split('.')
+                    column = int(column) + (len(sys.ps1) - 1)
+                    self.text.mark_set("insert", "%s.%d" % (line, column))
+               
+                if self.text.compare('insert', '==', 'end-1c'):
+                   if self.history_ismember() == True:
+                        self.history.history_prev(event)
+                        return "break"
+
+                elif self.text.compare('insert linestart', '<=', 'iomark'):
+                    # don't leave the input area
+                    return "break"
+                 
+
+    def key_down_callback(self, event):  
+
+        if self.text.compare('insert', '>=', 'iomark'):
+            # cursor inside current input
+            s = self.text.get('iomark', 'end-1c')
+
+            if s.find('\n') == -1:
+                # single line input
+
+                if self.text.compare('insert', '==', 'end-1c'):
+                    self.history.history_next(event)
+                    return "break"
+                else:
+                    self.text.mark_set('insert', 'end-1c')
+                    return "break"
+
+            else:
+                # multiline input
+ 
+                if self.text.compare('insert linestart', '==', \
+                   'iomark linestart'):
+                    # correction in cursor placement due to ">>>"
+                    line,column = self.text.index(INSERT).split('.')
+                    column = int(column) - (len(sys.ps1) - 1)
+                    if column < 1:
+                        column = 1
+                    self.text.mark_set("insert", "%s.%d" % (line, column))
+
+                if self.history_ismember() == True:
+                    if self.text.compare('insert', '==', 'end-1c'):
+                        self.history.history_next(event)
+                        return "break"
+                    elif self.text.compare('insert lineend', '==', 'end-1c'):
+                        return "break"                
+
     def get_standard_extension_names(self):
         return idleConf.GetExtensions(shell_only=True)