A panel that can be toggled between collapsed and expanded states. By default, the panel includes a heading region that can be clicked to toggle the control's state. For a subclass that already includes a more obvious button target, see CollapsibleWithHeadingButton.

Use a Collapsible panel on a home page or information pane where some information may not be interesting to certain users or at certain times.

This control was discussed in a user interface blog post.