This is odd. I wanted to change the configuration of my three button Logitech mouse (wired mouse) that I have connected to my iMac and although the right button is working, the System preferences pane shows a TWO button mouse. In System preferences I used to see a much larger screen for setting up the mouse where I could select what each one of the buttons functions were. Now it just shows a simple mouse. How can I get it to detect that my mouse is a three button? Using Mavericks and a Logitec M-BD53. I know the mouse is old, but the mouse is working but I can't see the proper configuration screen. HELP!!