Xephyr, xnest problerm

[Die Optimisten <inform@die-optimisten.net>]

Hello,
Very helpful tools!
May I ask you:
What can I do if mouse is captured inside the window, so keyboard-input 
is also limited to that.
How can I leave the window? Didn't find any docs telling sg about that,
only solution was to remotely login and kill Xephyr...
So there should be a shortcut/metakey to change input-focus?

Perhaps you can help,
thanks a lot!
Andrew
PS: Because i#n NOT in the mailing-list, please also CC: to inform(AT) 
die-optimisten.net