# CloseButton (filter, event)

A button that closes a subwindow when clicked. Its target may be specified using the For property; otherwise, it is the nearest subwindow ancestor of the CloseButton itself.

For
  (Symbol)
  If given, this names the target. The named component must be either an overlapping (non-background) child of a `ZSplit`, or a descendant of something that is. In the latter case, the actual target will be the `ZSplit` child, not the named descendant.

Behavior
  Like a Button, but before generating an event, closes its target (if the target is not already closed).
Shape
  The natural shape of its child (i.e., with no shrink or stretch), plus the border around the button.