If you can't seem to get your groups to collapse, the first thing to do is make sure that your snippets are in fact in your group. Snippets that are in a group will be narrower than snippets that are not in groups. They will also have the same outline color as the group they belong to. The second thing is to make sure that you are clicking on the groups arrow. Just clicking the group title will not collapse or expand it. It has to be the arrow.