Read:
http://wowprogramming.com/docs/secur.../Group_Headers
It describes most of the options.
You are not using custom conditions which is fine. But if you do not use them make sure to activate "showRaid = true" if you want to display raidframes aswell.
Additionally. Make sure to never call SetScale/SetWidth/SetHeight on a group header unit button. Otherwise incase you are in combat and a group header unit is spawned your layout will grab a taint.