Another newbie question

Well... better... that's more of a design issue.

Most of the GUI designs will indeed use use a vertical splitcontainer, with the treeview on the left panel (docked to full) and the data (textboxes, comboboxes, textboxes etc.) on the right panel.

Instead of using a panel with dedicated controls on the right panel, you may also want to check out the PropertyGrid, which is a very powerful control for displaying an item's properties and would suit your scenario very well.

Hope this is somehow of an answer to your question :).

Ah, I think you'll be using Visual Studio 2003, aren't you? Well, VS 2005 improved splitters and panels dramatically.
But, no worry, essentially there's no difference between the two. I meant that you can dock two panels (or another control for that matter), and put a splitter inbetween them. So, dock one left and one full, so you can use a vertical splitter.

PropertyGrid can indeed be used for updates. Just set its SelectedObject property to the object of your choice.

There's lots of information on the PropertyGrid on the internet and in the documentation, but if you have specific questions, let me know.

Hope this answers your question