Calendar Date LOV is not working in Query mode, while updating the record second time

Hi Every one,

I am having issue while selecting date LOV, when updating the record for second time.

When form is opened for first time. I was able to select the LOV for date field. It is calendar (Enable List Lamp).This columns is optional.

When user tries to query the record and trying to update the date using LOV on date field, calendar is not showing up.

I am using KEY-LISTVAL and WHEN-VALIDATE-ITEM triggers on this column.

In the KEY-LISTVAL tigger, I am using calendar.show;

Please provide me any suggestions/ work around to display LOV when user trying to update the date for second time.