In the attached construction, I used group g002-hexaunit to create some linked quadrilaterals. They all had to be in one group and the group had to be sketched in 3d because they need to "fold up" into three dimensions in a concerted way. Now I want to extrude one of the quadrilaterals. (Geometrically, it is constrained to be a rectangle, but it was not drawn with the rectangle tool so it wouldn't be constrained to a fixed plane.)

So I selected two of the edges of the rectangle and the point they met at and chose New Group > Sketch in New Workplane. That indeed created a plane parallel to the plane of that rectangle and a new group g003-sketch-in-plane. But now when I make that group active with "In Workplane" selected under the "Sketch" top bar menu, and then select all four edges of the rectangle as well as all four vertices and execute "Extrude", I get just a single line segment (connecting to the point I selected when I made the the Sketch in New Workplane perpendicular to the plane).

I have the sense that to extrude, the polygon selected has to be in the workplane not just geometrically (as it is) but also organizationally (i.e., listed when I select the group g003-sketch-in-plane). But I don't see how to pull those elements into the sketch, or copy them into it, or whatever it is I need to do.

Thanks so much for any guidance.