current-window returns the window in which the cursor is currently
displayed. The cursor always tracks the buffer-point of the corresponding
buffer. If the point is moved to a position which would be off the screen the
recentering process is invoked. Recentering shifts the starting point of the
window so that the point is once again displayed. The current window may be
changed with setf. Before the current window is changed, the hook Set
Window Hook is invoked with the new value.
Holds a list of all the window objects made with make-window.