You may have to change it to "middle button" or there may even be a choice for "zoom". I believe the default selection is "Universal scroll". You may have to play around with a few different options before you find the correct choice. Chances are it was being used as a different function. of China Hungary India Indonesia Ireland Israel Italy Jamaica Japan Kuwait Latvia Lithuania Luxembourg Macao S.A.R.Some of Logitechs drivers have an option in the Control Panel > Mouse that changes the behavior of the middle mouse wheel.