fixed dropdown disabled

src/lupermissionsedit.js

 '    <label class="col-sm-6 control-label">{{ permission.Name }}</label>' +
 '<div class="col-sm-6">' +
 '    <div class="btn-group">' +
-'    <a class="btn btn-default dropdown-toggle btn-select" data-toggle="dropdown" href="" lu-enable-permission="{{ luModelOptions.permissions.edit }}">' +
+'    <button class="btn btn-default dropdown-toggle btn-select" data-toggle="dropdown" href="" lu-enable-permission="{{ luModelOptions.permissions.edit }}">' +
 '    {{ permission.Value ? \'Allow\' : \'Disallow\' }} <span class="caret"></span>' +
-'    </a>' +
+'    </button>' +
 '    <ul class="dropdown-menu">' +
 '    <li><a href="" ng-click="editPermission(permission, false)">Disallow</a></li>' +
 '<li><a href="" ng-click="editPermission(permission, true)">Allow</a></li>' +
 '    <div class="clearfix"></div>' +
 '    <div class="col-sm-12" lu-busy="permission_add" lu-show-permission="{{ luModelOptions.permissions.add }}">' +
 '    <div class="btn-group">' +
-'    <a class="btn btn-default dropdown-toggle btn-select" data-toggle="dropdown" href="">' +
+'    <button class="btn btn-default dropdown-toggle btn-select" data-toggle="dropdown" href="">' +
 '    {{ tmpPermission.Name }} <span class="caret"></span>' +
-'    </a>' +
+'    </button>' +
 '    <ul class="dropdown-menu">' +
 '    <li ng-repeat="permission in allPermissionsCleared">' +
 '    <a href="" ng-click="tmpPermission.Name = permission.Name">{{ permission.Name}}</a>' +
 '</ul>' +
 '</div>' +
 '<div class="btn-group">' +
-'    <a class="btn btn-default dropdown-toggle btn-select" data-toggle="dropdown" href="">' +
+'    <button class="btn btn-default dropdown-toggle btn-select" data-toggle="dropdown" href="">' +
 '    {{ tmpPermission.Value ? \'Allow\' : \'Disallow\' }} <span class="caret"></span>' +
-'    </a>' +
+'    </button>' +
 '    <ul class="dropdown-menu">' +
 '    <li><a href="" ng-click="tmpPermission.Value = false">Disallow</a></li>' +
 '<li><a href="" ng-click="tmpPermission.Value = true">Allow</a></li>' +