+    class DemoCodeEditor(wx.TextCtrl):
+        def __init__(self, parent):
+            wx.TextCtrl.__init__(self, parent, -1, style =
+                                 wx.TE_MULTILINE | wx.HSCROLL | wx.TE_RICH2 | wx.TE_NOHIDESEL)
+
+        def RegisterModifiedEvent(self, eventHandler):
+            self.Bind(wx.EVT_TEXT, eventHandler)
+
+        def SetReadOnly(self, flag):
+            self.SetEditable(not flag)
+            # NOTE: STC already has this method
+    
+        def GetText(self):
+            return self.GetValue()
+
+        def GetPositionFromLine(line):
+            return self.XYToPosition(0,line)
+
+        def GotoLine(self, line):
+            pos = self.editor.GetPositionFromLine(line)
+            self.editor.SetInsertionPoint(pos)
+            self.editor.ShowPosition(pos)
+
+        def SelectLine(self, line):
+            start = self.GetPositionFromLine(line)
+            end = start + self.GetLineLength(line)
+            self.SetSelection(start, end)
+
+
+#---------------------------------------------------------------------------
+# Constants for module versions
+
+modOriginal = 0
+modModified = 1
+modDefault = modOriginal
+
+#---------------------------------------------------------------------------
+
+class DemoCodePanel(wx.Panel):
+    """Panel for the 'Demo Code' tab"""
+    def __init__(self, parent, mainFrame):
+        wx.Panel.__init__(self, parent, size=(1,1))
+        if 'wxMSW' in wx.PlatformInfo:
+            self.Hide()
+        self.mainFrame = mainFrame
+        self.editor = DemoCodeEditor(self)
+        self.editor.RegisterModifiedEvent(self.OnCodeModified)
+
+        self.btnSave = wx.Button(self, -1, "Save Changes")
+        self.btnRestore = wx.Button(self, -1, "Delete Modified")
+        self.btnSave.Enable(False)
+        self.btnSave.Bind(wx.EVT_BUTTON, self.OnSave)
+        self.btnRestore.Bind(wx.EVT_BUTTON, self.OnRestore)
+
+        self.radioButtons = { modOriginal: wx.RadioButton(self, -1, "Original", style = wx.RB_GROUP),
+                              modModified: wx.RadioButton(self, -1, "Modified") }
+
+        self.controlBox = wx.BoxSizer(wx.HORIZONTAL)
+        self.controlBox.Add(wx.StaticText(self, -1, "Active Version:"), 0,
+                            wx.RIGHT | wx.LEFT | wx.ALIGN_CENTER_VERTICAL, 5)
+        for modID, radioButton in self.radioButtons.items():
+            self.controlBox.Add(radioButton, 0, wx.EXPAND | wx.RIGHT, 5)
+            radioButton.modID = modID # makes it easier for the event handler
+            radioButton.Bind(wx.EVT_RADIOBUTTON, self.OnRadioButton)
+            
+        self.controlBox.Add(self.btnSave, 0, wx.RIGHT, 5)
+        self.controlBox.Add(self.btnRestore, 0)
+
+        self.box = wx.BoxSizer(wx.VERTICAL)
+        self.box.Add(self.controlBox, 0, wx.EXPAND)
+        self.box.Add(wx.StaticLine(self), 0, wx.EXPAND)
+        self.box.Add(self.editor, 1, wx.EXPAND)
+        
+        self.box.Fit(self)
+        self.SetSizer(self.box)
+
+
+    # Loads a demo from a DemoModules object
+    def LoadDemo(self, demoModules):
+        self.demoModules = demoModules
+        if (modDefault == modModified) and demoModules.Exists(modModified):
+            demoModules.SetActive(modModified)
+        else:
+            demoModules.SetActive(modOriginal)
+        self.radioButtons[demoModules.GetActiveID()].Enable(True)
+        self.ActiveModuleChanged()
+
+
+    def ActiveModuleChanged(self):
+        self.LoadDemoSource(self.demoModules.GetSource())
+        self.UpdateControlState()
+        self.ReloadDemo()
+
+        
+    def LoadDemoSource(self, source):
+        self.editor.Clear()
+        self.editor.SetValue(source)
+        self.JumpToLine(0)
+        self.btnSave.Enable(False)
+
+
+    def JumpToLine(self, line, highlight=False):
+        self.editor.GotoLine(line)
+        self.editor.SetFocus()
+        if highlight:
+            self.editor.SelectLine(line)
+        
+       
+    def UpdateControlState(self):
+        active = self.demoModules.GetActiveID()
+        # Update the radio/restore buttons
+        for moduleID in self.radioButtons:
+            btn = self.radioButtons[moduleID]
+            if moduleID == active:
+                btn.SetValue(True)
+            else:
+                btn.SetValue(False)
+
+            if self.demoModules.Exists(moduleID):
+                btn.Enable(True)
+                if moduleID == modModified:
+                    self.btnRestore.Enable(True)
+            else:
+                btn.Enable(False)
+                if moduleID == modModified:
+                    self.btnRestore.Enable(False)
+
+                    
+    def OnRadioButton(self, event):
+        radioSelected = event.GetEventObject()
+        modSelected = radioSelected.modID
+        if modSelected != self.demoModules.GetActiveID():
+            busy = wx.BusyInfo("Reloading demo module...")
+            self.demoModules.SetActive(modSelected)
+            self.ActiveModuleChanged()
+
+
+    def ReloadDemo(self):
+        if self.demoModules.name != __name__:
+            self.mainFrame.RunModule()
+
+                
+    def OnCodeModified(self, event):
+        self.btnSave.Enable(self.editor.IsModified())
+
+        
+    def OnSave(self, event):
+        if self.demoModules.Exists(modModified):
+            if self.demoModules.GetActiveID() == modOriginal:
+                overwriteMsg = "You are about to overwrite an already existing modified copy\n" + \
+                               "Do you want to continue?"
+                dlg = wx.MessageDialog(self, overwriteMsg, "wxPython Demo",
+                                       wx.YES_NO | wx.NO_DEFAULT| wx.ICON_EXCLAMATION)
+                result = dlg.ShowModal()
+                if result == wx.ID_NO:
+                    return
+                dlg.Destroy()
+            
+        self.demoModules.SetActive(modModified)
+        modifiedFilename = GetModifiedFilename(self.demoModules.name)
+
+        # Create the demo directory if one doesn't already exist
+        if not os.path.exists(GetModifiedDirectory()):
+            try:
+                os.makedirs(GetModifiedDirectory())
+                if not os.path.exists(GetModifiedDirectory()):
+                    wx.LogMessage("BUG: Created demo directory but it still doesn't exit")
+                    raise AssetionError
+            except:
+                wx.LogMessage("Error creating demo directory: %s" % GetModifiedDirectory())
+                return
+            else:
+                wx.LogMessage("Created directory for modified demos: %s" % GetModifiedDirectory())
+            
+        # Save
+        f = open(modifiedFilename, "wt")
+        source = self.editor.GetText()
+        try:
+            f.write(source)
+        finally:
+            f.close()
+            
+        busy = wx.BusyInfo("Reloading demo module...")
+        self.demoModules.LoadFromFile(modModified, modifiedFilename)
+        self.ActiveModuleChanged()
+
+
+    def OnRestore(self, event): # Handles the "Delete Modified" button
+        modifiedFilename = GetModifiedFilename(self.demoModules.name)
+        self.demoModules.Delete(modModified)
+        os.unlink(modifiedFilename) # Delete the modified copy
+        busy = wx.BusyInfo("Reloading demo module...")
+        self.ActiveModuleChanged()