Select Always Returning First Item of List (AngularJS)

No matter what I select, this function only returns the first item of the list. As requested, I have included the complete JS code. I have looked through this code four hours and everything seems right to me. This is my first contact with Angular and any help will be greatly appreciated! Thank you!

HTML

<div class="form-horizontal input-append">
    <select name="selectedSharedTenantId"  data-ng-model="selectedSharedTenantId">
        <option data-ng-repeat="item in getFilteredTenants()" value="{{item.id}}">{{item.displayName}}</option>
    </select>
    <button type="button" class="btn" ng-click="addSharedTenant();">
        <i class="fas fa-plus"></i>
    </button>
</div>

JS

$scope.addSharedTenant = function () {
    alert($scope.selectedSharedTenantId)
}

COMPLETE JS CODE

angular.module('directives.datasetEditor', [
    'services.dataset',
    'ui.bootstrap'
])

.directive('datasetEditor', ['$modal', 'DatasetServices', function ($modal, DatasetServices) {
    return {
        restrict: 'A',
        scope: {
            tenantId: '=',
            tenants: '=',
            originalModel: '=model',
            callback: '&callback'
        },
        link: function(scope, element, attrs) {
            scope.model = scope.originalModel ? angular.copy(scope.originalModel) : {
                entryType: 'Activity',
                displayName: ''
            };

            var ModalInstanceCtrl = ['$scope', '$modalInstance',
                function($scope, $modalInstance) {
                    var setSelectedSharedTenantId = function () {
                        var selectedTenant = $scope.getFilteredTenants()[0];
                        $scope.selectedSharedTenantId = selectedTenant ? selectedTenant.id : null;
                    };

                    $scope.getFilteredTenants = function () {
                        return _.filter($scope.tenants, function (o) {
                            alert(o.id)
                            return _.indexOf($scope.model.sharedTenantIds, o.id) == -1 && o.id != $scope.tenantId;
                        });
                    };

                    $scope.getTenantById = function (id) {
                        return _.findWhere($scope.tenants, {
                            id: id
                        });
                    };


                    $scope.removedSharedTenant = function (id) {
                        $scope.model.sharedTenantIds = _.without($scope.model.sharedTenantIds, id);
                        var selectedTenant = $scope.getFilteredTenants()[0];
                        setSelectedSharedTenantId();
                    };

                    $scope.addSharedTenant = function () {
                        //alert($scope.selectedSharedTenantId)
                        //alert($scope.model.sharedTenantIds)
                        if ($scope.selectedSharedTenantId) {
                            if ($scope.model.sharedTenantIds == null) {
                                $scope.model.sharedTenantIds = [];
                            }
                            $scope.model.sharedTenantIds.push($scope.selectedSharedTenantId);
                            setSelectedSharedTenantId();
                        }
                    };

                    $scope.submit = function(isValid) {
                        if (isValid) {
                            DatasetServices.save($scope.model).success(function(data, status, headers, config) {
                                $modalInstance.close(data);
                            });
                        } else {
                            $scope.submitted = true;
                        }
                    };

                    $scope.cancel = function() {
                        $modalInstance.dismiss();
                    };

                    $scope.submitted = false;
                    setSelectedSharedTenantId();
            }];

            function open() {
                var modalInstance = $modal.open({
                    templateUrl: '../pkg/wisdom/common/angular/directives/dataset-editor/index.html',
                    controller: ModalInstanceCtrl,
                    scope: scope
                });

                modalInstance.result.then(
                    function(model) {
                        scope.callback({
                            model: model
                        });
                    },
                    function() {
                    }
                );
            };

            element.on('click', open);
        }
    };
}]);