Is it possible to make the Agreement and Supplier fields mandatory in Purchase Requisition?

I have a requirement from a client to make the Agreement and Supplier field mandatory in Requisition page.

I have been answered in one of the community discussion I commented on:
Is it mandatory to have a Source Agreement for Import Requisitions to AutoGenerate Purchase Order?
https://community.oracle.com/customerconnect/discussion/comment/1108919#Comment_1108919

I was able to make the Agreement field mandatory through Page Composer, as discussed in the community discussion above.
However, when I make both Agreement and Supplier fields mandatory, it does not allow me to Save/Submit without the other.

Thus, I have a follow up question?