@@ -1610,11 +1610,16 @@ class DotWidget(gtk.DrawingArea):

             self.y += self.POS_INCREMENT/self.zoom_ratio

             self.queue_draw()

             return True

-        if event.keyval == gtk.keysyms.Page_Up:

+        if event.keyval in (gtk.keysyms.Page_Up,

+                            gtk.keysyms.plus,

+                            gtk.keysyms.equal,

+                            gtk.keysyms.KP_Add):

             self.zoom_image(self.zoom_ratio * self.ZOOM_INCREMENT)

             self.queue_draw()

             return True

-        if event.keyval == gtk.keysyms.Page_Down:

+        if event.keyval in (gtk.keysyms.Page_Down,

+                            gtk.keysyms.minus,

+                            gtk.keysyms.KP_Subtract):

             self.zoom_image(self.zoom_ratio / self.ZOOM_INCREMENT)

             self.queue_draw()

             return True