That was most certainly not the practice in the past, and I question this motion now.
Basically, when a study was proposed and agreed to by the committee, each party would put forward a list of witnesses they would want to appear. Again, it was a fairly collegial process that ensured that every party had its witnesses appear before the committee in proportion to the party's representation on the committee.
I don't see what would be served by the motion on the floor right now, at all.