HandlerRegistration addPaneChangedHandler(PaneChangedHandler handler)
currentPanechanges, either due to end-user action or due to a programmatic call to
setCurrentPane()or other APIs that can change the pane.
Note that depending on the
DeviceMode, this event may not signal that any pane has
actually been shown or hidden, since in some modes multiple panes are shown simultaneously.
Never fires while the
SplitPane is not drawn.
handler- the paneChanged handler
HandlerRegistrationused to remove this handler