Hold down Cmd + Opt + click on the triangle icon will collapse or expand all level layer groups.

按下Cmd和Opt键的同时击这个三角形符号，可以折叠或展开所有层级的群组文件夹。

youdao

If it turns out that this doesn't open the avenues for research that Bush says it will, then I think you're going to get a lot of pressure from the scientific community and from all the patients groups that want to expand this a lot further.

CNN: Reporter: Stem cell decision may open door for lawsuits