initially assign focus to SketchWidget

SketchWidget.py

@@ -44,6 +44,7 @@ class SketchWidget:
                         gtk.gdkgl.MODE_DEPTH))
 
         self.widget = gtk.gtkgl.DrawingArea(self.glconfig)
+        self.widget.set_flags(gtk.CAN_FOCUS)
 
         self.widget.connect_after('realize', self.init)
         self.widget.connect('configure_event', self.reshape)

Window.py

@@ -47,6 +47,8 @@ class Window:
         self.window.add(vbox)
         self.window.show_all()
 
+        sw.widget.grab_focus()
+
     def main(self):
         gtk.main()