Well, I'm back. I solved the ListBox problem by using a ContextMenuStrip — or so I thought!
It comes in perfect, then in a quarter second, two things happen: it disappears, and the TreeNode unselects.
But for that quarter second, it looks perfect!
The way that progresses is, I step through the lines of code on the right of the screenshot, 5 lines, then one more F11, and it appears for a 1/4 second, and the TreeNode UNSELECTS.
But here's another interesting thing:
In Design Mode, I clicked the reference to contextMenuStrip1 in the dialog bar beneath the Form, and it appears in the place I dropped it.
Then a click on the TreeView (white as I suppose you know) and it disappears.
Ah, but then I take the mouse and pull the TreeView over to the right, again click the reference below, again the ContextMenuStrip appears, then I click the TreeView, and AGAIN it disappears!
What am I missing, dear friends? Something to do with the focus?
Much obliged for any help.