Clicking a button within a form causes page refresh

I have a form in Angular that has two buttons tags in it. One button submits the form on ng-click. The other button is purely for navigation using ng-click. However, when this second button is clicked, AngularJS is causing a page refresh which triggers a 404. I’ve dropped a breakpoint in the function and it is triggering my function. If I do any of the following, it stops:

1. If I remove the ng-click, the button doesn’t cause a page refresh.
2. If I comment out the code in the function, it doesn’t cause a page refresh.
3. If I change the button tag to an anchor tag (<a>) with href="", then it doesn’t cause a refresh.

The latter seems like the simplest workaround, but why is AngularJS even running any code after my function that causes the page to reload? Seems like a bug.

Here is the form:

<form class="form-horizontal" name="myProfile" ng-switch-when="profile">
  <fieldset>
    <div class="control-group">
      <label class="control-label" for="passwordButton">Password</label>
      <div class="controls">
        <button id="passwordButton" class="secondaryButton" ng-click="showChangePassword()">Change</button>
      </div>
    </div>

    <div class="buttonBar">
      <button id="saveProfileButton" class="primaryButton" ng-click="saveUser()">Save</button>
    </div>
  </fieldset>
</form>

Here is the controller method:

$scope.showChangePassword = function() {
  $scope.selectedLink = "changePassword";
};