* There's some problem with the focus.
    + Some windows are not focused on creation.
    + The mouse have be above this windows to get the focus.
    + If one window is moved outside the mouse pointer and another window is 
      below the mouse, the later is focused.
* Check how to delete (?) the socket with an unsuccesful exit.
* Change the socket interface with IPC ?
* Implement Fullscreen properly.
* Implement a nice focus with the keys.
* Implement close window.