checkbox_buttons.slim in engine2-1.0.9

- old
+ new

@@ -1,6 +1,6 @@
 .col-lg-12
-  .btn-group.btn-group-sm ng-init="(action.record[f] === undefined) && (action.record[f] = field.render.false_value)" ng-model="action.record[f]" e2-field=""
+  .btn-group.btn-group-sm ng-init="(action.record[f] === null || action.record[f] === undefined) && (action.record[f] = field.render.false_value)" ng-model="action.record[f]" e2-field=""
     a.btn.btn-default ng-class="action.record[f] === field.render.true_value && 'active'" ng-click="action.record[f] = field.render.true_value" ng-disabled="field.disabled"
       span.glyphicon.glyphicon-check
     a.btn.btn-default ng-class="action.record[f] === field.render.false_value && 'active'" ng-click="action.record[f] = field.render.false_value" ng-disabled="field.disabled"
       span.glyphicon.glyphicon-unchecked