An operation input system and method are provided. The system includes a display device including a display screen, an input device that provides an input into the display device and a control device that includes a protrusion control section that controls a protrusion state of each of the plurality of protrusion members in accordance with a display content in the windows displayed on the display screen. The system is controlled such that when a first window and a second window are displayed so as to partially overlap each other, the protrusion control section makes the protrusion state of the protrusion members protruded in accordance with the display content of a hidden region of the second window different from the protrusion state of the protrusion members protruded in accordance with the display content of an entire region of the first window.