What do you mean? It is a feature that the game uses less resources if the program is in the background, so naturally the FPS drop as well. I would not recommend to disable that feature.
http://duion.com I don't want no Unity, I just want my Torque 3D.
Duion I mean when the program is in the background, but it is show. If there is no window in rect of it. The fps do not drop.If there is a window in rect in it,the fps drop.