onBeforeContextMenu event is fired when user clicks a Tree item directly before the popup menu is shown. You should use this event to customize menu for a particular Tree item (for example, disable or enable some menu command).
Two parameters are passed to the handler:
You may return false from this handler to cancel the menu pop-up.
ganttChartControl.attachEvent("onBeforeContextMenu", function(menu,obj) { // A sample of disabling menu for a particular task item: if (obj.getId()==15) return false; if (obj.isProject) { // Project menu menu.setItemText("m1", "Project: " + obj.getName()); menu.setUserData("","obj",{type:"p",o:obj}); } else if (obj.isTask) { // Task menu menu.setItemText("m1", "Task: " + obj.getName()); menu.setUserData("","obj",{type:"t",o:obj}); } });