JavaScript/jQuery Gantt - contextMenu

$(function () {
    $("#gantt").dxGantt({
        contextMenu: {
            enabled: false
        }            
    });
});  

$(function () {
    $("#gantt").dxGantt({
        contextMenu: {
            items: [
                "addTask",
                "deleteTask",
                {
                    text: "Zoom",
                    items: [
                        "zoomIn",
                        "zoomOut"
                    ]
                }
            ]
        }
        //...            
    });
});  

$(function () {
    $("#gantt").dxGantt({
        contextMenu: {
            items: [
                {
                    text: "Category",
                    items:[
                        {
                            text: "Item 1",
                            name: "item1"
                        },
                        {
                            text: "Item 2",
                            name: "item2"
                        },
                        {
                            text: "Item 3",
                            name: "item3"
                        }                        
                    ]                        
                }
                // ...
            ]
        }
        onCustomCommand: onCustomCommandClick
        // ...
    });
});
function onCustomCommandClick(e) {
    if(e.name == 'item1') {
        // your code
    }
}