GroupSystem::adjustData

protected function adjustData($data, LeftMenuUser $user): array
{
	$collapseMode = $this->getCollapseMode($this->getId());
	if ($collapseMode === null)
	{
		$collapseMode = $this->defaultOptions['collapsed_mode'] ?? null === 'expanded' ? 'expanded' : 'collapsed';
	}

	$data['PARAMS']['collapse_mode'] = $collapseMode;

	return parent::adjustData($data, $user);
}