This is kinda a new issue for me and I'm not sure what could have caused the change. When I use the quick buttons ONLY in the group window the Group windows option screen appears. It seems to happen on all six slots.
did you modify the txt file to include any groupsay chat messages? if so, you cant use /g (i know from first hand goof ups) to say in group chat. That will open up the group options window.
When I was adding a /gsay I used the command "group" which is putting the text in /gsay but it is popping up the group options. I am going to try gsay instead and see if that resolves.