@@ -1615,9 +1615,8 @@ class DotWidget(gtk.DrawingArea):

         width = abs(x1 - x2)

         height = abs(y1 - y2)

         if width == 0 and height == 0:

-            self.zoom_ratio /= 2

+            self.zoom_ratio *= self.ZOOM_INCREMENT

         else:

-            # TODO: handle case of width or hight == 0

             self.zoom_ratio = min(

                 float(rect.width)/float(width),

                 float(rect.height)/float(height)