Window switching focus

I have just installed Inner Space as well as ISboxer. Working from the tutorials I got ISboxer working with Rift and was able to have a small group working effectively. I have a small issue though at seemingly random times during play the focus will switch from one character to an other. I do not believe I am clicking in any subwindow to cause the switch. I am using F11 and F12 to target and assist. As I write this I realize there may be a default key assigned to ISboxer to cause a screen switch but if that is not the case does anyone have any ideas why this might be happening?