We have already started to get some bugs on the new group window, So i am trying to help you understand what is going on. The devs want a more minimalistic gui so the start of this was to bring you guys a brand new buddy window. The testers have taken a lot of time trying to get some changes made to this window but overall the function of the window and the look has not changed since it was added to SVN several months ago. When you first open the window you will only see a scrollbar there is no way to disable this and there is no background for this window like the others have. You will notice that there is nothing in the window untill you go and invite someone to your group, but just a sec where did that invite button go?? If you right click on it [or control click for you mac users, yes that works in this release in several places] you will see the options you are looking for, invite leave and disband. You will also notice there is no title bar in this window so the only way to close it is to leave your group, disband your group or use the icon on the toolbar to close the group window. One improvment in this window we have made since it was introduced is a background for the names of the members of the groups, in light colored maps it was very hard to read the names so you have that as one fix to this window since it was made.
bug 950
http://www.hydlaa.com/flyspray_upgrade/index.php?do=details&task_id=950 has more information on this window and questions we as testers have brought up to the devs.
Please add any ideas for fixing this window or patches to the bug linked above. I believe both the testers and the Devs are willing to look into other options for making this and other windows look better to let us know if you have ideas.