Override Gantt functionality to update visible headers, columns and tasks on horizontal scroll.

gantt.css

/*
Workaround for gantt tooltips not showing when gantt-scrollable has horizontal scroll and its parent has an animation.
*/
.gantt-task-info {
  -webkit-animation-fill-mode: both;
  animation-fill-mode: both;
  -webkit-animation-duration: 0s;
  animation-duration: 0s;
  -webkit-animation-name: fadeIn;
  animation-name: fadeIn;
}

gantt.js

(function (angular) {

    /**
     * Override Gantt functionality to update visible headers, columns and tasks on horizontal scroll.
     */

    function GanttColumnsManagerDecorator($delegate) {

        $delegate.prototype.updateVisibleColumns = function (includeViews) {
            this.visibleColumns = this.columns;

            this.visibleHeaders = [];
            for (var i = 0; i < this.headers.length; i++) {
                this.visibleHeaders.push(this.headers[i]);
            }

            if (includeViews) {
                for (i = 0; i < this.visibleColumns.length; i++) {
                    this.visibleColumns[i].updateView();
                }
                for (i = 0; i < this.visibleHeaders.length; i++) {
                    var headerRow = this.visibleHeaders[i];
                    for (var j = 0; j < headerRow.length; j++) {
                        headerRow[j].updateView();
                    }
                }
            }

            var currentDateValue = this.gantt.options.value('currentDateValue');
            this.gantt.currentDateManager.setCurrentDate(currentDateValue);
        };

        return $delegate;
    }

    function GanttRowDecorator($delegate, $filter) {

        $delegate.prototype.updateVisibleTasks = function () {
            var filterTask = this.rowsManager.gantt.options.value('filterTask');
            if (filterTask) {
                if (typeof(filterTask) === 'object') {
                    filterTask = {model: filterTask};
                }

                var filterTaskComparator = this.rowsManager.gantt.options.value('filterTaskComparator');
                if (typeof(filterTaskComparator) === 'function') {
                    filterTaskComparator = function (actual, expected) {
                        return filterTaskComparator(actual.model, expected.model);
                    };
                }

                this.filteredTasks = $filter('filter')(this.tasks, filterTask, filterTaskComparator);
            } else {
                this.filteredTasks = this.tasks.slice(0);
            }
            this.visibleTasks = this.filteredTasks;
        };

        return $delegate;
    }

    GanttColumnsManagerDecorator.$inject = ['$delegate'];
    GanttRowDecorator.$inject = ['$delegate', '$filter'];

    angular.module('gantt')
        .decorator('GanttColumnsManager', GanttColumnsManagerDecorator)
        .decorator('GanttRow', GanttRowDecorator);

})(angular);