Mystagogue,

1. AFAIK that sliding feature is called "auto-hide". I personally don't know
if the winforms supports it out of the box.

2. Most often when programmers use splitters they put two panels separated
by a splitter and then add more controls to the panels. Because this is the
usual configuration MS decided to create it as a control - one panel
containing two other panels separated by a splitter. Nesting this controls
one can get any configuration one wants.

Whether using this control or the splitter control itself is up to you. If
you do complex splitting you'll end up creating split containers by
yourself, so why don't just use already created one; for simple splitting
you can save 3 panels if you use the simple Splitter control.

Here's a free third-party control that gives you the slide-outs as well as
tabbed-MDI forms:
http://sourceforge.net/projects/dockpanelsuite/

Be sure to also download the VB Cookbook document in the Files section.
That will get you up and running rather quickly.