handlesMouseOver:

Do I want to receive mouseEnter: and mouseLeave: when the button is up and the hand is empty? The default response is false, except if you have added sensitivity to mouseEnter: or mouseLeave:, using the on:send:to: mechanism.

initialize

mouseLeave:

Handle a mouseLeave event, meaning the mouse just left my bounds with no button pressed. The default response is to let my eventHandler, if any, handle it.