Virtuoso XL problem

hi.
   I am using Virtuoso XL editor in Candence 4.4.6. When I click on
one terminal in the layout, the corresponding net in the schematic will
be highlighted. However, when I click on another terminal on the layout,
the old highlighted net keeps the highlight color and doesn't switch back
anymore. Is there any way to solve this problem?

   Thank you!

sincerely
-------------
Kuan Zhou
ECSE department