Access Subdatasheet (plus sign) not showing in datasheet view form but shows in table or query

I want to show inside a form in datasheet view, the plus signs for viewing subdatasheet. I have tables properly linked, all is fine and I have subdatasheet set in table/query and it displays correctly and all information well linked.

I have a form based on that table/query that has the subdatasheet but when I open the form in datasheet view so that I can see the subdatasheet, this wont show up. The plus signs are not there.

I just want a form for looking up data, not for editing and subdatasheet view serves perfectly what I want to achieve but I don’t want to open tables or queries directly but inside a form.