code: function() {
      this.jsonInit({
        "message0": Blockly.Msg.SENSING_SETDRAGMODE,
        "args0": [
          {
            "type": "field_dropdown",
            "name": "DRAG_MODE",
            "options": [
              [Blockly.Msg.SENSING_SETDRAGMODE_DRAGGABLE, 'draggable'],
              [Blockly.Msg.SENSING_SETDRAGMODE_NOTDRAGGABLE, 'not draggable']
            ]
          }
        ],
        "category": Blockly.Categories.sensing,
        "extensions": ["colours_sensing", "shape_statement"]
      });
    }
docs: Block to set drag mode.
  @this Blockly.Block