Validation required in sourcing cockpit

Hello All,

We are in need to doing some validations to the PO in the sourcing cockpit (after edit selected drafts is clicked and the po is opened in another tab).

I tried with the DOC_CHECK_BADI (however this gets triggered sometimes only). Also the PO details are not available in the BADI sometimes, which I am not sure about. Is this right BADI to do this validation? Pls advise if you have worked on a similar requirement before. If there is a class to enhance.. which would be the right one for this requirement?

In another note, when does DOC_CHECK_BADI get triggered during PO create/ change? It has to be here... in the Sourcing Cockpit right?? Please let me know.

TIA, Liz