[meld] meldwindow: Hook up the GtkShortcutWindow where possible

[Kai Willadsen <kaiw src gnome org>]

commit 0039034eb8f67e27464dfb3c1bf05dc54dbc0698
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Thu Feb 11 06:52:30 2016 +1000

    meldwindow: Hook up the GtkShortcutWindow where possible

 meld/meldwindow.py |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/meld/meldwindow.py b/meld/meldwindow.py
index 49b77cb..6b3d488 100644
--- a/meld/meldwindow.py
+++ b/meld/meldwindow.py
@@ -21,6 +21,7 @@ from gi.repository import Gio
 from gi.repository import GLib
 from gi.repository import Gtk
 
+import meld.ui.util
 from . import dirdiff
 from . import filediff
 from . import filemerge
@@ -259,6 +260,14 @@ class MeldWindow(gnomeglade.Component):
         rmenu = self.ui.get_widget('/Menubar/FileMenu/Recent').get_submenu()
         rmenu.connect("map", self._on_recentmenu_map)
 
+        try:
+            builder = meld.ui.util.get_builder("shortcuts.ui")
+            shortcut_window = builder.get_object("shortcuts-meld")
+            self.widget.set_help_overlay(shortcut_window)
+        except GLib.Error:
+            # GtkShortcutsWindow is new in GTK+ 3.20
+            pass
+
     def _on_recentmenu_map(self, recentmenu):
         for imagemenuitem in recentmenu.get_children():
             imagemenuitem.set_tooltip_text(imagemenuitem.get_label())