Unable to set default value to the Multiselect combo in query form

Hi,

I have requirement to set default value to the multiselect combo in query form. I have applied this multiselect control to the parametric entity and through the expression I am trying to set the default values to this control. I am returning Id's in the expression and for some reason this control is not setting default values when I run the query form. Any suggestions on this is much appreciated.

Thank you!