In sum, I wanted the action of clipping something to a new entry in RN to make that entry the current one, to simultaneously put the cursor on that entry in the tree (same thing, I suppose) and to scroll the tree to show it. The way RN currently operates seem to me less than logical. It's presumably the author's preference, but maybe my preference could be made a configuration option.
I just realized that there is at least one workflow context in which RN's current behavior is logical and beneficial; I should have thought of this earlier because I often use it myself! Let's say we are collecting web excerpts or pages on topic A, and want to have each as a separate note (or sub-node) under topic A. If the tree focus is on the A node as parent, then RN's behavior allows us to successively clip as many items as we wish from our web browser without ever going back to RN. The result will be as many new sibling notes, all under A.
So RN provides the following two options for clipping web excerpts or capturing web pages, each with its own dedicated, configurable hotkey:
1. Add new notes
under a parent node.
2. Append new content
to an existing note.
In both cases, the action applies to the focused node of the tree, and the focus remains on that node after the action. Because the focus doesn't move, we can continue to add more notes or append more content from the browser without returning to RN.
And likewise in both cases, we must first select the target node in RN before clipping or capturing from a web browser. If we do that, I think RN will easily compile multiple clips into one note just as you described. Now that I understand this, I see that it is logical and consistent.
The auto scrolling is a separate but related matter which I think could be improved. I will send Rael my suggestions for that.
[EDIT: I just found that the method for inserting a new Web clip can be configured in Tools > Clipper Options. It can be added either as a child of the current note or at the bottom of the tree.]