ui-calendar tooltip function not working

calendar to display a calendar and set of events(events being hardcoded as of now).But when i hover on the event the tooltip is not displayed.I searched for many answers online and none worked for me ,Everything else except tooltip is working.Please help.Following is my js code

var app = angular.module('myApp', ['ui.calendar', 'ui.router']);
app.controller('myNgController', ['$scope', '$http', 'uiCalendarConfig', function($scope, $http, uiCalendarConfig) {

    $scope.SelectedEvent = null;
    var isFirstTime = true;

    $scope.events = [];
    $scope.eventSources = [$scope.events];
    $scope.events.push({
        title: "event",
        description: "jahsojoaisjjoijaso",
        start: new Date("2017-05-03"),
        end: new Date("2017-05-03"),
        allDay: false,
        stick: false
    });

    $scope.uiConfig = {
        calendar: {
            height: 450,
            editable: false,
            displayEventTime: false,
          
            header: {
                left: 'month basicWeek basicDay agendaWeek agendaDay',
                center: 'title',
                right: 'today prev,next'
            },
            eventClick: function(event) {
                $scope.SelectedEvent = event;
            },
            eventAfterAllRender: function() {
                if ($scope.events.length > 0 && isFirstTime) {
                    //Focus first event
                    uiCalendarConfig.calendars.myCalendar.fullCalendar('gotoDate', $scope.events[0].start);
                    isFirstTime = false;
                }
            }
        }
    };
    
    
    
    $scope.eventRender = function( event, element, view ) { 
        element.attr({'tooltip': event.title,
                     'tooltip-append-to-body': true});
        $compile(element)($scope);
    };

}]);

and if i try the following code the whole event disappears.The event is no more displayed on the calender

var app = angular.module('myApp', ['ui.calendar', 'ui.router']);
app.controller('myNgController', ['$scope', '$http', 'uiCalendarConfig', function($scope, $http, uiCalendarConfig) {

    $scope.SelectedEvent = null;
    var isFirstTime = true;

    $scope.events = [];
    $scope.eventSources = [$scope.events];
    $scope.events.push({
        title: "event",
        description: "jahsojoaisjjoijaso",
        start: new Date("2017-05-03"),
        end: new Date("2017-05-03"),
        allDay: false,
        stick: false
    });

    $scope.uiConfig = {
        calendar: {
            height: 450,
            editable: false,
            displayEventTime: false,
          
            header: {
                left: 'month basicWeek basicDay agendaWeek agendaDay',
                center: 'title',
                right: 'today prev,next'
            },
            eventClick: function(event) {
                $scope.SelectedEvent = event;
            },
            eventAfterAllRender: function() {
                if ($scope.events.length > 0 && isFirstTime) {
                    //Focus first event
                    uiCalendarConfig.calendars.myCalendar.fullCalendar('gotoDate', $scope.events[0].start);
                    isFirstTime = false;
                }
            },
            eventRender : function( event, element, view ) { 
                element.attr({'tooltip': event.title,
                             'tooltip-append-to-body': true});
                $compile(element)($scope);
            }
        }
    };

}]);

and the html code

<h1> calendar</h1>
            <div ng-controller="myNgController">
               <div class="row">
                  <div class="col-md-8">
                     <div id="calendar" ui-calendar="uiConfig.calendar" ng-model="eventSources" calendar="myCalendar"></div>
                  </div>
                  <div class="col-md-4">
                     <div class="alert alert-success" style="margin-top:50px" ng-controller="MyDbController">
                        <h2 style="margin-top:0px;text-align:center;" ng-repeat="elem in data"> {{elem.balance}}  Available  </h2>
                        <a ui-sref="apply" onclick="closeNav()" class="btn btn-success" role="button" style="display: block; margin: 0 auto;" >Reques(s)</a>
                     </div>
                  </div>
               </div>
            </div>

updated code as per answer ..

var app = angular.module('myApp', ['ui.calendar', 'ui.router']);
app.controller('myNgController',['$scope', '$timeout', '$http', '$compile', 'uiCalendarConfig', function($scope, $timeout, $http, $compile, uiCalendarConfig){

    $scope.SelectedEvent = null;
    var isFirstTime = true;

    $scope.events = [];
    $scope.eventSources = [$scope.events];
    $scope.events.push({
        title: "event",
        description: "jahsojoaisjjoijaso",
        start: new Date("2017-05-03"),
        end: new Date("2017-05-03"),
        allDay: false,
        stick: false
    });

    $scope.uiConfig = {
        calendar: {
            height: 450,
            editable: false,
            displayEventTime: false,
          
            header: {
                left: 'month basicWeek basicDay agendaWeek agendaDay',
                center: 'title',
                right: 'today prev,next'
            },
            eventClick: function(event) {
                $scope.SelectedEvent = event;
            },
            eventRender : function( event, element, view ) { 
                element.attr({'tooltip': event.title,
                             'tooltip-append-to-body': true});
                $compile(element)($scope);
            },
            eventAfterAllRender: function() {
                if ($scope.events.length > 0 && isFirstTime) {
                    //Focus first event
                	$timeout(function(){
                	uiCalendarConfig.calendars.myCalendar.fullCalendar('gotoDate', $scope.events[0].start);
                    isFirstTime = false;
                });
                }
            }
           
            
        }
    };

Solution

You must set that function in the calendar configuration definition (Reference):

$scope.uiConfig = {
    calendar: {
        eventRender: $scope.eventRender,
        ... reset of the configuration
    }
}

Don't forget to inject $compile to your controller:

app.controller('myNgController', ['$scope', '$http', '$compile', 'uiCalendarConfig', function($scope, $http, $compile, uiCalendarConfig) {

As for our discussion in the comments - You're getting "TypeError: Cannot read property 'fullCalendar' of undefined" error. Try the following

Inject $timeout to the controller:

app.controller('myNgController', ['$scope', '$timeout', '$http', '$compile', 'uiCalendarConfig', function($scope, $timeout, $http, $compile, uiCalendarConfig) {

And wrap this line with $timeout:

uiCalendarConfig.calendars.myCalendar.fullCalendar('gotoDate', $scope.events[0].start);

So the final result will be:

$timeout(function() {
    uiCalendarConfig.calendars.myCalendar.fullCalendar('gotoDate', $scope.events[0].start);
});

This will make sure that you call fullCalendar only after the view was finished rendering.

And for dessert - Take a look on how you set the tooltip:

element.attr({
    'tooltip': event.title,
    'tooltip-append-to-body': true
});

Note that it adds tooltip="<title of event> and tooltip-append-to-body="true, but in order to show the tooltip, you need to set a title attribute. Change it to:

element.attr({
    'title': event.title,
    'tooltip-append-to-body': true
});

I guess that you think it's Bootstrap.UI tooltip (http://angular-ui.github.io/bootstrap/#!#tooltip) so in that case you need to make the necessary changes to implement it correctly. But using title will ensure that while hovering over the event the browser will show you the default tooltip (Using the native HTML "title" attribute).