First, let me pick one minor nit: the fact that the up/down arrows move the rectangle indicates that, in fact, that pane does have focus. Windows maintains a distinction between focus, which refers to the window that gets the keyboard input (and some other things if exclusively focused), and selection, which refers to the status of items in that pane. In multi-selection enabled controls, for example, you can move a rectangle around because the control has the focus but change the selection status by pressing space bar. A lot of users don't realize there's a distinction because they're so used to single-selection list-boxes, combo-boxes, etc.
Second, thank you so much for your observation. I find it mostly works for what I'm after. I say 'mostly' because the up/down arrows do not work at all when you first launch the application if it has only the "Home" tab open on the right. In that state, nothing done on the keyboard seems to get you back to the left pane, not even the up/down arrows. Once you use the mouse to open a new tab, however, then you can at least use the up/down arrows. I don't understand why they work only if another tab is open, but that seems to be the case. Try it and see if you find any different. For now I'm marking your answer as the correct one. I think this is going to require the folks at VMware to fix the unwelcome inconsistency.
