Image two panels, top and bottom. The top one lists all of the panels; the bottom one is details. When you mouse over a panel, the details show up in the bottom pane. Which is great, except that the details run off the *bottom* of the pane. And of course, if you move the mouse to go to the scrollbar for the bottom pane, it loses the panel selection. Very special.
Eventually, I twigged that you could click on the panel, which "locks" it into place so that you get get to the scrollbar. At least, it makes it the default -- if you move the mouse over any *other* panel, it switches to that. But it's at least possible to read the details, once you figure the UI out. However, any design that involves "figure the UI out" is a bad design, pretty much by definition.
I have to say, my faith in these people who are supposed to be teaching me is not very high right now...