I want to retrieve item information when I hover the mouse over it. I tried the example of an earlier question but it doesn't work. It shows the title but not the content (Bootstrap popover over $(this) element)

    [...]
                    demoSource.push({
                                name: RFInum,
                        desc: deadline,
                                values: [{
                                    from: start,
                                    to: end,
                                    label: tit,
                                    customClass: balk_kleur,
                        dataObj: stat
                }],

        var popoverContent;
                        $(".gantt").gantt({
                            source: demoSource,
                            navigate: "scroll",
                            scale: "days",
                            maxScale: "months",
                            minScale: "hours",
                            itemsPerPage: 20,
                            scrollToToday: false,
                            useCookie: true,
                            onItemClick: function(data) {
                            },
                    onItemMouseover: function(elm, data) {
                                popoverContent = data.detailContent;
            alert(popoverContent);
                        },
                            onAddClick: function(dt, rowId) {
                                alert("Empty space clicked - add an item!");
                            },
                            onRender: function() {
                                if (window.console && typeof console.log === "function") {
                                    console.log("chart rendered");
                                }
                            }
                        });
            
                        $(".gantt").popover({
                            selector: ".bar",
                            title: function _getItemText() {
                                return this.textContent;
                            },
                            container: '.gantt',
                            content: function () {
                            return popoverContent;
                        },
                            trigger: "hover",
                            placement: "auto right"
                        });
    [...]