[FIX] web: Form: only render button StatButton

One could want to render something else than a `button` in the
buttonbox (even if the name seems to imply that it will contain
buttons).

In this case, we render the method corresponding to the tag instead
of a button.

addons/web/static/src/js/views/form/form_renderer.js

@@ -251,12 +251,19 @@ return BasicRenderer.extend({
      * @returns {jQueryElement}
      */
     _renderButtonBox: function (node) {
+        var self = this;
         var $result = $('<' + node.tag + '>', { 'class': 'o_not_full' });
         // Avoid to show buttons if we are in create mode (edit mode without res_id)
         if (this.mode === 'edit' && !this.state.res_id) {
             return $result;
         }
-        var buttons = _.map(node.children, this._renderStatButton.bind(this));
+        var buttons = _.map(node.children, function (child) {
+            if (child.tag === 'button') {
+                return self._renderStatButton(child);
+            } else {
+                return self._renderNode(child);
+            }
+        });
         var buttons_partition = _.partition(buttons, function ($button) {
             return $button.is('.o_form_invisible');
         });

addons/web/static/tests/views/form_tests.js

@@ -2644,6 +2644,34 @@ QUnit.module('Views', {
         form.destroy();
     });
 
+    QUnit.test('diplay something else than a button in a buttonbox', function (assert) {
+        assert.expect(3);
+
+        var form = createView({
+            View: FormView,
+            model: 'partner',
+            data: this.data,
+            arch: '<form>' +
+                    '<div name="button_box" class="oe_button_box">' +
+                        '<button type="object" class="oe_stat_button" icon="fa-check-square">' +
+                            '<field name="bar"/>' +
+                        '</button>' +
+                        '<label/>' +
+                    '</div>' +
+                '</form>',
+            res_id: 2,
+        });
+
+        assert.strictEqual(form.$('.oe_button_box').children().length, 2,
+            "button box should contain two children");
+        assert.strictEqual(form.$('.oe_button_box .oe_stat_button').length, 1,
+            "button box should only contain one button");
+        assert.strictEqual(form.$('.oe_button_box label').length, 1,
+            "button box should only contain one label");
+
+        form.destroy();
+    });
+
     QUnit.test('one2many default value creation', function (assert) {
         assert.expect(1);