What happens is this:
1) within the skin, a button is defined as an "ncmd" or nghost-command action type. For our example we'll say it's Navit.
2) user clicks the button and nGhost launches the application remembering it's PID and WindowID.
3) user returns back to nghost to play music or whatever.
4) when the user clicks the "Navit" button again, instead of relaunching the application, nGhost will attempt to bring Navit's window into focus.
I have found that not all window managers support the window managing technique that nGhost uses (which has been abstracted from wmctrl, and rewritten in c++). Also, some applications change their PID on startup (ie firefox), in which case, nGhost won't be able to keep track of it... This may be tweaked later to also query the windowID by either window name or process name in addition to the current pid lookup...
There is no default support rearview cam support in nghost/linuxice. there shouldn't be a problem getting it to work like it should with virtual no effort (besides getting it installed and launching it via icepanel/nghost).
probably more than you asked for hehe.