Using %lw causes winio@ to return whilst leaving the window open. ctrl is
a control variable that is returned with the value -1. Subsequently the window
can be closed by setting ctrl to zero (or a positive value) and calling
window_update@(ctrl). Setting ctrl to -2 will cause the window to close after
after a short delay. This can be used to seamlessly modify a window by closing the
window and then recreating it with similar features and the same position and size.
%lw can take the option owned ( %lw[owned] ). This option defines
certain properties of the window in relation to its parent. The "owned"
properties are those of a window that does not use %lw, namely that the parent
cannot overlay the child and, if the parent is closed, the child automatically
closes. For these properties to be meaningful the parent must be created using
%ww - Window Style. Also %lw[owned] must be used in the definition of a child window that
appears in a call-back function of the parent.