protected function computeIsTransparent()
	{
		foreach ($this->branches as $branch)
		{
			foreach ($branch as $element)
			{
				if (!ElementInspector::isTransparent($element))
				{
					$this->isTransparent = false;

					return;
				}
			}
		}
		$this->isTransparent = !empty($this->branches);
	}