Currently the only way to have children hidden by default is by applying the following patch: http://confluence.atlassian.com/display/DISC/Hiding+Children+by+Default

It would be very, very useful to negate the need for this patch through a UserInterfaceState.properties file which sets the defaults. This properties file could be used to add easy customisation that doesn't require source compilation without cluttering up the admin UI with lots of small switches. This is only a suggested solution, anything that provides a way of optionally hiding children by default without the need for custom themeing or source hacking would likely be acceptable.