private function addContainer(WidgetContainerConfig $containerWidget)
{
$widgetId = $containerWidget->getId();
$this->container[$widgetId] = $containerWidget;
// widgets were added to this container, but the container did not exist yet.
if (isset($this->containerWidgets[$widgetId])) {
foreach ($this->containerWidgets[$widgetId] as $widget) {
$containerWidget->addWidgetConfig($widget);
}
unset($this->containerWidgets[$widgetId]);
}
}