Multiple Monitor Issues [Client]

I have been experiencing an issue using more than one monitor. When I enter a game, the LoL client will occasionally refuse to lock my cursor on the main monitor where the client is running. This leads to not being able to "edge scroll" my screen to the right(where my second monitor is setup. I have to minimize the client multiple times in order to fix this issue. I have tried restarting the client as well as my computer. I would like to start playing ranked matches but am unwilling to lose 3-5 minutes fixing my screen. If anyone knows why this is happening or what I can do to fix it I would be very grateful.

LordAkiris