Deal with this by adding ED_view3d_init_mats_rv3d(ob, r3d) which initialized the region mat's and is used in mesh_foreachScreenVert, mesh_foreachScreenEdge etc.
Deal with this by adding ED_view3d_init_mats_rv3d(ob, r3d) which initialized the region mat's and is used in mesh_foreachScreenVert, mesh_foreachScreenEdge etc.