Compile ignores my selection

I am not sure by what actual mechanism in the software you refer to as “selecting the parts”, as there are a few different ways of doing so—each with their own particular advantages.

You might find this post, along with the thread discussion itself, to be helpful as it goes into detail on some of these methods. There I discuss my preferred method for quickly compiling “one-off” selections.

But that aside, it would help to know more precisely what you are doing, so that the underlying problem can perhaps be understood. A good way of doing that is with a copy of the tutorial, in the Help menu, so that we’re all using the same material and settings. Then, by documenting each step you take with as much detail as possible, show how to achieve the effect you suspect is a bug.