@@ -1614,10 +1614,14 @@ class DotWidget(gtk.DrawingArea):

         rect = self.get_allocation()

         width = abs(x1 - x2)

         height = abs(y1 - y2)

-        self.zoom_ratio = min(

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

-            float(rect.height)/float(height)

-        )

+        if width == 0 and height == 0:

+            self.zoom_ratio /= 2

+        else:

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

+            self.zoom_ratio = min(

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

+                float(rect.height)/float(height)

+            )

         self.zoom_to_fit_on_resize = False

         self.x = (x1 + x2) / 2

         self.y = (y1 + y2) / 2