Minimizing League of Legends Client to tray, after the game starts

Don't think I am the only one who have this issue, for most of players it may be alright, but we (me and players with bad PCs) have problems with horrible FPS drops, because Alpha client does not minimize itself to system tray after game launches, it stays open and it causes fps drops from 60 to 10 and even 6 sometimes. Not sure if its bug, but please Riot make it go to tray like previous client. The rest is awesome and client is OP

thanks for attention, that's all :)