Android - Can I make Home folders close on click?
I haven't tried it myself, but from what I am reading in forums, etc, Apps Organizer is a free app that does what you are looking for. When you select an app in a folder, it closes the folder.
EDIT: update - I just tried out Apps Organizer. It does close the folder when you select something. The only problem is that it appears to only allow app shortcuts - not bookmarks, widgets, etc. There appear to be other apps (Folder Organizer) that are able to hold bookmarks, however.