Mouse Button Control converts Middle-Mouse-Button-Click to a Double-Click. It is as if you pressed the left-mouse-button two time very quickly. This is handy if you do not need the Middle-Mouse-Button, but do a lot of Double-Clicks.
Converts the four arrow keys to mouse moves option. To press an arrow key will move the mouse cursor one pixel. This is handy if you want to use the mouse to highlight and grab something, and continue to hold down the left mouse button while tapping the arrow keys. This allows you to move an object precisely where you want it. You can turn this option on and off as needed.