$uibModal doesn't show my UI in my angular webpack project

Question

I am calling below function on ng-click of a button.

vm.updateSourceAndVisibility = function(skus) {
  $log.info("In updateSourceAndVisibility");
  var modal = $uibModal.open({
    animation: true,
    template: require('./source-selection/source.selection.html'),
    controller: require('./source-selection/source.selection.controller.js'),
    controllerAs: 'sourceSelectCtrl',
    backdrop : 'static',
    size: 'md'
  });
};

When I click that button, a modal comes up having just

/src/app/pages/src/source-selection/source.selection.html

But source.selection.html has this HTML,

<form name="sourceSelectForm" novalidate>

  <!-- modal header -->
  <div class="modal-header">
    <button type="button" class="close" data-dismiss="modal" aria-label="Close" ng-click="sourceSelectCtrl.close()"><span aria-hidden="true">&times;</span></button>
      <h4 class="modal-title">Select Sources</h4>
  </div>

  <!-- modal body -->
  <div class="modal-body">
      <!-- Source information -->
      <div class="row">
        I want to put something here
      </div>
  </div>

  <!-- modal footer -->
  <div class="modal-footer">
    <button type="button" class="btn btn-default" ng-click="sourceSelectCtrl.close()">Cancel</button>
    <button type="submit" class="btn btn-primary" ng-click="sourceSelectCtrl.submit()">Select</button>
  </div>

</form>

What did I do wrong?