Cursor moved to center of screen when game gets automatically paused

This can be very annoying as it can lead to clicking on things you didn't intend to in any app.

Steps to reproduce on Windows

1. Open a new world
2. Alt-tab to another program (or use windows key to open the start menu)
3. Minecraft is no longer in focus
4. As soon as auto pause kicks in, cursor will be moved to dead center on the screen

Steps to reproduce on OS X

1. Disable auto-pause using F3+P
2. Stand in a Nether portal
3. Switch to another fullscreen app
4. As soon as the Nether loads, the cursor will suddenly be in the center of the screen.

(This ticket was originally reported by xPaw.)