I discovered this by accident today, force of habit from Firefox 
It makes the new tab window with similar/parallel resources much more accessible if you tend to navigate by keyboard...
But it's not in any of the documentation on Keyboard Shortcuts...
I note in the help file that there are shortcuts fro Ctrl-Tab, Ctrl-Shift-Tab for switching between panes, but these are nothing like what I'd expect (again from firefox ). I'd expect Ctrl-Tab to rotate in order between the tabs of the active pane, and Ctrl-Shift-Tab to do the same in reverse (ie it does within a program what Alt-Tab does at OS level)
