I have no problems playing FTB packs itself with crashes/lag but when I try to use 2 windows at once, side by side and I click away from the FTB window, when I click back onto it the size is reset into the default minecraft size/position; I have tried using the .jar and .exe launchers as well as setting the size in the launcher advanced options (but not the position) but it still resets to the default size. Just a not i'm running on Windows 7 x64 bit.