Visitor messed up my mouse. How to get it to insert?

Visitor messed up my wire mouse (white oval 1 button) Now insert hard to place, wants to block too much text or shows a block of choices in a white box. I'd love to turn the box off, and keep things as simple as they were before. I don't understand what the words mean on the System Prefs for the mouse. Please help. Can anyone tell me how to turn things off or differently?

Thanks