Application.setVariableValue

I am trying to use the application.setvariableValue in the onselect event for a date field. After the date is entered, the query should execute and the values in the crosstab should change. However the data is not changing.

the following is the code in the onselect event:

datefilter = DATEFIELD_1.getDate();

APPLICATION.setVariableValue("0P_KEYDT",datefilter);

is there a step I am missing.  I am executing locally.

thanks for the help.