Group Private Message

I am not sure if this is a new problem on my forum or not but I would like some help. When I go to my Private Message box I can send a message to a group by clicking the drop down box and selecting the group I wish to send a PM to. The problem is when I or someone else wants to REPLY to a group message the drop down menu is not clickable so you either have to add each indivisual user or send multiple messages to each member. Can someone help me out on this please.

Moderators can't send group PM's back. It does not work like an email.