So far I have two separate sketches in a single part, as shown below:

Here Sketch1 is shown selected for feature application.  Sketch2 is fully defined wrt. points on Sketch1, also fully defined.  The extra vertical lines from the center line up to the lower-left corner of the rectangle and from the center of the center-point arc up to its end point are both construction lines, so that Sketch2 is "open."  The intention was to create a hollow cylinder from Sketch1 and then attach to it a thin shell based on Sketch 2.  I did it this way to make sure that the second revolve feature was not dependent on an edge of the first but was controlled instead by the original sketch.

My problem is that, either sketch I select for the Revolved Boss/Base feature, the feature always gets applied to Sketch2.  Only after that can I apply the same feature to Sketch1.  Why can't I apply it to Sketch1 first?

After both revolves are done, I also think I can see in cross section views a visible separation between the two revolved solids.  I believe this would not have happened if I had revolved Sketch1 first.  Correct? -- John Willett