John,

If you need such urgent help, it would help if you posted just what values you are assigning.

>I set dynamicforecolor and dynamicbackcolor expression to get the effect of grid highlight. It works fine. However, my user complaint that error "Dynamic forecolor/backcolor expresssion is invalid" will be occured after the application run for period of time, usually after 6-8 hours. WHY?
>The application is POS front end.