VBCS: Select single is replacing SDP filterCriterion with key attributes value in q param

Summary:

I have defined a Select single in a form layout. I have assigned SDP variable, based on Fusion ADF describe REST API, to that select single and a Value property.

When there is no Value, the select single will call the SDP with the filterCriterion defined at SDP level. But when there is a value in that select single, its ignoring the filterCriterion and appending the q parameter based on key attribute of SDP with the Value.

How can I tell the SDP to include always the filterCriterion along with q parameter so that underlying REST API will execute with out failure.