I don't know where i can found this on any forum so i create one and hops some1 will answer me.
I run very often dual-monitor (47" LG TV + 22" Samsung tv), Samsung is my main monitor and LG is my second monitor.
Only program i use on LG is VLC (yeah you know, movie, serie ect...),
watch this when i play games on my main monitor.
Only game i have played (most often...) is DD (dungeon defender) and playing full-mode with out any problem at alls.
when i tested LoL then when i move my mouse to right side then my mouse go over to my second monitor
Tested all screen options in LoL and its not does work
So the only questions i have to tel is if you know what program och whatever i need to do so i can play LoL without my mouse curse will go over to next monitor.
Like disable to move curse to next monitor, or program that you stuck in-game so when you need to get out you need to press some button. just my theory.