Help in Always one selected value in list box.

[#1]

Dear all,

I have created a list box with field being given in variable and used in list box through expression .

As, i use the field through expression the feature always select one value Option get disabled.

So, is there is any way how to always select any one value while the data in list box is in Expression.

Please suggest any answer.

Kind Regards,

Pranav

[#2]

Is there any way we can enable always one selected option for calculated fields in list box?