{
  "title": "Trackball tools",
  "rules": [
    {
      "description": "The wheel click is fired by pressing the left and right buttons simultaneously.",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "simultaneous": [
              { "pointing_button": "button1" },
              { "pointing_button": "button2" }
            ],
            "simultaneous_options": {
              "key_up_when": "all"
            },
            "modifiers": {
              "mandatory": [
              ],
              "optional": [
              ]
            }
          },
          "to": [
            {
              "pointing_button": "button3",
              "modifiers": [
              ]
            }
          ]
        }
      ]
    }
  ]
}