diff --git a/Lib/idlelib/Debugger.py b/Lib/idlelib/Debugger.py
index a82fdbb..30d0002 100644
--- a/Lib/idlelib/Debugger.py
+++ b/Lib/idlelib/Debugger.py
@@ -331,7 +331,7 @@
         for editwin in pyshell_edit_windows:
             filename = editwin.io.filename
             try:
-                for lineno in editwin.get_current_breaks():
+                for lineno in editwin.breakpoints:
                     self.set_breakpoint_here(filename, lineno)
             except AttributeError:
                 continue
diff --git a/Lib/idlelib/IOBinding.py b/Lib/idlelib/IOBinding.py
index 594ecf6..a90157e 100644
--- a/Lib/idlelib/IOBinding.py
+++ b/Lib/idlelib/IOBinding.py
@@ -13,28 +13,9 @@
 import tkFileDialog
 import tkMessageBox
 import re
+
 from configHandler import idleConf
 
-#$ event <<open-window-from-file>>
-#$ win <Control-o>
-#$ unix <Control-x><Control-f>
-
-#$ event <<save-window>>
-#$ win <Control-s>
-#$ unix <Control-x><Control-s>
-
-#$ event <<save-window-as-file>>
-#$ win <Alt-s>
-#$ unix <Control-x><Control-w>
-
-#$ event <<print-window>>
-#$ win <Control-p>
-#$ unix <Control-x><Control-p>
-
-#$ event <<save-copy-of-window-as-file>>
-#$ win <Alt-Shift-s>
-#$ unix <Control-x><w>
-
 try:
     from codecs import BOM_UTF8
 except ImportError:
@@ -85,11 +66,12 @@
 encoding = encoding.lower()
 
 coding_re = re.compile("coding[:=]\s*([-\w_.]+)")
+
 def coding_spec(str):
-
     """Return the encoding declaration according to PEP 263.
-    Raise LookupError if the encoding is declared but unknown."""
 
+    Raise LookupError if the encoding is declared but unknown.
+    """
     # Only consider the first two lines
     str = str.split("\n")[:2]
     str = "\n".join(str)
@@ -107,6 +89,7 @@
         raise LookupError, "Unknown encoding "+name
     return name
 
+
 class IOBinding:
 
     def __init__(self, editwin):
@@ -218,14 +201,14 @@
         self.set_filename(filename)
         self.text.mark_set("insert", "1.0")
         self.text.see("insert")
-
         self.updaterecentfileslist(filename)
         return True
 
     def decode(self, chars):
-        # Try to create a Unicode string. If that fails, let Tcl try
-        # its best
+        """Create a Unicode string
 
+        If that fails, let Tcl try its best
+        """
         # Check presence of a UTF-8 signature first
         if chars.startswith(BOM_UTF8):
             try:
@@ -237,7 +220,6 @@
                 # Indicates that this file originally had a BOM
                 self.fileencoding = BOM_UTF8
                 return chars
-
         # Next look for coding specification
         try:
             enc = coding_spec(chars)
@@ -248,19 +230,16 @@
                 "installation. The file may not display correctly" % name,
                 master = self.text)
             enc = None
-
         if enc:
             try:
                 return unicode(chars, enc)
             except UnicodeError:
                 pass
-
         # If it is ASCII, we need not to record anything
         try:
             return unicode(chars, 'ascii')
         except UnicodeError:
             pass
-
         # Finally, try the locale's encoding. This is deprecated;
         # the user should declare a non-ASCII encoding
         try:
@@ -295,8 +274,8 @@
         else:
             if self.writefile(self.filename):
                 self.set_saved(1)
+                self.editwin.store_file_breaks()
         self.text.focus_set()
-
         return "break"
 
     def save_as(self, event):
@@ -305,8 +284,8 @@
             if self.writefile(filename):
                 self.set_filename(filename)
                 self.set_saved(1)
+                self.editwin.store_file_breaks()
         self.text.focus_set()
-
         self.updaterecentfileslist(filename)
         return "break"
 
@@ -315,7 +294,6 @@
         if filename:
             self.writefile(filename)
         self.text.focus_set()
-
         self.updaterecentfileslist(filename)
         return "break"
 
@@ -326,7 +304,6 @@
             f = open(filename, "w")
             f.write(chars)
             f.close()
-            ## print "saved to", `filename`
             return True
         except IOError, msg:
             tkMessageBox.showerror("I/O Error", str(msg),
@@ -338,14 +315,12 @@
             # This is either plain ASCII, or Tk was returning mixed-encoding
             # text to us. Don't try to guess further.
             return chars
-
         # See whether there is anything non-ASCII in it.
         # If not, no need to figure out the encoding.
         try:
             return chars.encode('ascii')
         except UnicodeError:
             pass
-
         # If there is an encoding declared, try this first.
         try:
             enc = coding_spec(chars)
@@ -358,17 +333,14 @@
                 return chars.encode(enc)
             except UnicodeError:
                 failed = "Invalid encoding '%s'" % enc
-
         if failed:
             tkMessageBox.showerror(
                 "I/O Error",
                 "%s. Saving as UTF-8" % failed,
                 master = self.text)
-
         # If there was a UTF-8 signature, use that. This should not fail
         if self.fileencoding == BOM_UTF8 or failed:
             return BOM_UTF8 + chars.encode("utf-8")
-
         # Try the original file encoding next, if any
         if self.fileencoding:
             try:
@@ -380,7 +352,6 @@
                     % self.fileencoding,
                     master = self.text)
                 return BOM_UTF8 + chars.encode("utf-8")
-
         # Nothing was declared, and we had not determined an encoding
         # on loading. Recommend an encoding line.
         try:
@@ -469,11 +440,8 @@
                                                   filetypes=self.filetypes)
         return self.savedialog.show(initialdir=dir, initialfile=base)
 
-
     def updaterecentfileslist(self,filename):
-        #
-        # Updates recent file list on all editor windows
-        #
+        "Update recent file list on all editor windows"
         self.editwin.UpdateRecentFilesList(filename)
 
 def test():
diff --git a/Lib/idlelib/PyShell.py b/Lib/idlelib/PyShell.py
index cf93613..f6e85f7 100644
--- a/Lib/idlelib/PyShell.py
+++ b/Lib/idlelib/PyShell.py
@@ -67,10 +67,6 @@
 class PyShellEditorWindow(EditorWindow):
     "Regular text edit window when a shell is present"
 
-    # XXX KBK 10Dec02 Breakpoints are currently removed if module is modified.
-    # In the future, it may be possible to preserve breakpoints by changing
-    # their line numbers as a module is modified.
-
     def __init__(self, *args):
         self.breakpoints = []
         apply(EditorWindow.__init__, (self,) + args)
@@ -78,11 +74,12 @@
         self.text.bind("<<clear-breakpoint-here>>", self.clear_breakpoint_here)
         self.text.bind("<<open-python-shell>>", self.flist.open_shell)
 
-        self.breakpointPath=os.path.join(idleConf.GetUserCfgDir(), 'breakpoints.lst')
-
+        self.breakpointPath = os.path.join(idleConf.GetUserCfgDir(),
+                                           'breakpoints.lst')
         # whenever a file is changed, restore breakpoints
         if self.io.filename: self.restore_file_breaks()
-        def filename_changed_hook(old_hook=self.io.filename_change_hook,self=self):
+        def filename_changed_hook(old_hook=self.io.filename_change_hook,
+                                  self=self):
             self.restore_file_breaks()
             old_hook()
         self.io.set_filename_change_hook(filename_changed_hook)
@@ -148,49 +145,82 @@
                 pass
 
     def store_file_breaks(self):
-        if not self.breakpoints:
-            return
-        filename=self.io.filename
+        "Save breakpoints when file is saved"
+        # XXX 13 Dec 2002 KBK Currently the file must be saved before it can
+        #     be run.  The breaks are saved at that time.  If we introduce
+        #     a temporary file save feature the save breaks functionality
+        #     needs to be re-verified, since the breaks at the time the
+        #     temp file is created may differ from the breaks at the last
+        #     permanent save of the file.  A break introduced after a save
+        #     will be effective,  but not persistent.  This is necessary to
+        #     keep the saved breaks synched with the saved file.
+        #
+        #     Breakpoints are set as tagged ranges in the text.  Certain
+        #     kinds of edits cause these ranges to be deleted: Inserting
+        #     or deleting a line just before a breakpoint, and certain
+        #     deletions prior to a breakpoint.  These issues need to be
+        #     investigated and understood.  It's not clear if they are
+        #     Tk issues or IDLE issues, or whether they can actually
+        #     be fixed.  Since a modified file has to be saved before it is
+        #     run, and since self.breakpoints (from which the subprocess
+        #     debugger is loaded) is updated during the save, the visible
+        #     breaks stay synched with the subprocess even if one of these
+        #     unexpected breakpoint deletions occurs.
+        breaks = self.breakpoints
+        filename = self.io.filename
         try:
-            lines=open(self.breakpointPath,"r").readlines()
+            lines = open(self.breakpointPath,"r").readlines()
         except IOError:
-            lines=[]
-        new_file=open(self.breakpointPath,"w")
+            lines = []
+        new_file = open(self.breakpointPath,"w")
         for line in lines:
-            if not line.startswith(filename+"="):
+            if not line.startswith(filename + '='):
                 new_file.write(line)
-        new_file.write(filename+"="+`self.get_current_breaks()`+"\n")
+        self.update_breakpoints()
+        breaks = self.breakpoints
+        if breaks:
+            new_file.write(filename + '=' + str(breaks) + '\n')
         new_file.close()
 
     def restore_file_breaks(self):
         self.text.update()   # this enables setting "BREAK" tags to be visible
-        filename=self.io.filename
+        filename = self.io.filename
+        if filename is None:
+            return
         if os.path.isfile(self.breakpointPath):
-            lines=open(self.breakpointPath,"r").readlines()
+            lines = open(self.breakpointPath,"r").readlines()
             for line in lines:
-                if line.startswith(filename+"="):
-                    breakpoint_linenumbers=eval(line[len(filename)+1:]) 
+                if line.startswith(filename + '='):
+                    breakpoint_linenumbers = eval(line[len(filename)+1:]) 
                     for breakpoint_linenumber in breakpoint_linenumbers:
                         self.set_breakpoint(breakpoint_linenumber)
 
-    def get_current_breaks(self):
-        #
-        # retrieves all the breakpoints in the current window
-        #
+    def update_breakpoints(self):
+        "Retrieves all the breakpoints in the current window"
         text = self.text
-        lines = text.tag_ranges("BREAK")
-        result = [int(float((lines[i]))) for i in range(0,len(lines),2)]
-        return result
- 
-    def saved_change_hook(self):
-        "Extend base method - clear breaks if module is modified"
-        if not self.get_saved():
-            self.clear_file_breaks()
-        EditorWindow.saved_change_hook(self)
+        ranges = text.tag_ranges("BREAK")
+        linenumber_list = self.ranges_to_linenumbers(ranges)
+        self.breakpoints = linenumber_list
+
+    def ranges_to_linenumbers(self, ranges):
+        lines = []
+        for index in range(0, len(ranges), 2):
+            lineno = int(float(ranges[index]))
+            end = int(float(ranges[index+1]))
+            while lineno < end:
+                lines.append(lineno)
+                lineno += 1
+        return lines
+
+# XXX 13 Dec 2020 KBK Not used currently
+#    def saved_change_hook(self):
+#        "Extend base method - clear breaks if module is modified"
+#        if not self.get_saved():
+#            self.clear_file_breaks()
+#        EditorWindow.saved_change_hook(self)
 
     def _close(self):
         "Extend base method - clear breaks when module is closed"
-        self.store_file_breaks()
         self.clear_file_breaks()
         EditorWindow._close(self)