Chameleon Sheet Should Dispatch "Close" Event

[ryuhhnn]

Is your feature request related to a problem? Please describe. If you are working in stateless components, it's hard to manage the state of the chameleon sheet and knowing whether or not the sheet was closed via clicking on the "close" button.

Describe the solution you'd like A custom event is dispatched whenever the sheet closes so that stateless components can capture and respond to this event to reset their state.