if (this.binding != null) {
FaceletContext ctx = (FaceletContext) context.getAttributes().get(FaceletContext.FACELET_CONTEXT_KEY);
expression = this.binding.getValueExpression(ctx, PanelToggleListener.class);
}
PanelToggleSource source = (PanelToggleSource) parent;
source.addPanelToggleListener(new LazyPanelToggleListener(this.listenerType, expression));
}