undo_actions

sets the actions that the Undo operation will revert

object undo_actions;

gantt.config.undo_actions = {
    update: "update",
    remove: "remove", // remove an item from datastore
    add: "add",
    move: "move"
};

Details

This option is defined in the undo extension, so you need to enable the undo plugin. Read the details in the Undo/Redo Functionality article.