When I play Minecraft in BOTH windowed or fullscreen mode it seems as though my cursor isn't bound to the Minecraft window. I have two monitors so this may be the cause. My main monitor (the one Minecraft is displayed on) is on the left and my secondary monitor is on the right.

In Minecraft, when I turn my player to the right, the cursor will freely move to my second monitor. If I don't notice this and click like I'm trying to open a chest or crafting table, whatever my cursor had been moved over becomes the active window and sometimes Minecraft minimizes itself. I have tried restarting my PC.
Likewise, if I move my cursor up, Minecraft's window bar appears and stays until I move the cursor back down again. Also, if I move my cursor down too much, my Windows taskbar appears until I move my cursor back up again.

Basically, I have to be very aware of where I am moving my cursor otherwise my computer will focus on something else other than Minecraft and it is very distracting and ruins the immersion. Please help!