fCalloutClosed = function(oEvent) {
			if (oEvent.getSource()) {
				oEvent.getSource().destroyContent();
			}
			if (this._oCallout) {
				this._oCallout.$().css("display", "none");
			}
		}
This is to ensure that all content is destroyed when the Callout is
closed. Otherwise the content is destroyed when the Callout should be
opened again. But who knows if the user will really do this :-)?