Hello,
Yes, this was the root cause. Thank you 
Authorization group was maintained for this document type.
This was resolved. Now DP documents are displayed along with DA and DZ documents.
But now there is another one issue because of these auth groups.
For downpayments (DZ document type) there is a requirement to release them via VKM3 t-code. This one works Ok.
But now same works for DPR (DP document type) documents also. How can I disable that one?
They have different authorization groups.