diff -r decf52efb7f7 -r e0f16317668e dialogs/IDMergeDialog.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dialogs/IDMergeDialog.py	Thu Nov 22 23:39:54 2018 +0100
@@ -0,0 +1,48 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# See COPYING file for copyrights details.
+
+from __future__ import absolute_import
+import wx
+
+# class RichMessageDialog is still not available in wxPython 3.0.2 
+class IDMergeDialog(wx.Dialog):
+    def __init__(self, parent, title, question, optiontext, button_texts):
+        wx.Dialog.__init__(self, parent, title=title)
+
+        main_sizer = wx.BoxSizer(wx.VERTICAL)
+
+        message = wx.StaticText(self, label=question)
+        main_sizer.AddWindow(message, border=20,
+                             flag = wx.ALIGN_CENTER_HORIZONTAL | wx.TOP | wx.LEFT | wx.RIGHT)
+
+        self.check = wx.CheckBox(self, label=optiontext)
+        main_sizer.AddWindow(self.check, border=20,
+                             flag=wx.LEFT | wx.RIGHT | wx.BOTTOM | wx.ALIGN_CENTER_HORIZONTAL)
+
+        buttons_sizer = wx.BoxSizer(wx.HORIZONTAL)
+        for label,wxID in zip(button_texts, [wx.ID_YES, wx.ID_NO, wx.ID_CANCEL]):
+            Button = wx.Button(self, label=label)
+            def OnButtonFactory(_wxID):
+                return lambda event: self.EndModal(_wxID)
+            self.Bind(wx.EVT_BUTTON, OnButtonFactory(wxID), Button)
+            buttons_sizer.AddWindow(Button)
+
+        main_sizer.AddSizer(buttons_sizer, border=20,
+                            flag=wx.LEFT | wx.RIGHT | wx.BOTTOM | wx.ALIGN_RIGHT)
+
+        self.SetSizer(main_sizer)
+        self.Fit()
+
+        self.Bind(wx.EVT_CHAR_HOOK, self.OnEscapeKey)
+
+    def OnEscapeKey(self, event):
+        keycode = event.GetKeyCode()
+        if keycode == wx.WXK_ESCAPE:
+            self.EndModal(wx.ID_CANCEL)
+        else:
+            event.Skip()
+
+    def OptionChecked(self):
+        return self.check.GetValue()