Thank you for taking the time to look this over for me, Hartmut. I really do appreciate it. I am not really skilled in .php. I can read it and write it if I have to, but it's often kind of scary for me. It's a muscle I need to flex, more, I'm sure, and I'm getting the experience now, with Moodle.
But I know CSS! And so the very last post in your thread really got my attention. I love the elegance of it-don't bother shutting things off or modifying how they work, just don't bother to show them!
But in Justin's code, as quoted by Ray in the last post of the thread, there are a couple of classes:
.block_navigation .type_system.depth_2 { display: none; }
...and similar. I cannot find these anywhere in our v2.1 installation. I can find several of the .block_navigation and several .tree_item, but not these two, together. And I am not certain where the .type_name are being generated and what to look for ( _setting, _system, _user, etc. ) there. What value would I plug-in there for the type_name, in that second class, to indicate Reports and Participants?
Anyone know where I can write a simple { display: none; } rule for the Participants and Reports links, in the navigation block? This looks the most promising, to me. Thanks, again!