diff --git a/spec/parser/javascript/subexp_spec.js b/spec/parser/javascript/subexp_spec.js
new file mode 100644
index 0000000..a0bd550
--- /dev/null
+++ b/spec/parser/javascript/subexp_spec.js
@@ -0,0 +1,102 @@
+import javascript from 'src/js/parser/javascript/parser.js';
+import Node from 'src/js/parser/javascript/node.js';
+import _ from 'lodash';
+import Snap from 'snapsvg';
+import Q from 'q';
+
+describe('parser/javascript/subexp.js', function() {
+
+  beforeEach(function() {
+    Node.state = { groupCounter: 1 };
+  });
+
+  _.forIn({
+    '(test)': {
+      label: 'group #1',
+      regexp: jasmine.objectContaining({ textValue: 'test' }),
+      proxy: undefined,
+      state: { groupCounter: 2 }
+    },
+    '(?=test)': {
+      label: 'positive lookahead',
+      regexp: jasmine.objectContaining({ textValue: 'test' }),
+      proxy: undefined,
+      state: { groupCounter: 1 }
+    },
+    '(?!test)': {
+      label: 'negative lookahead',
+      regexp: jasmine.objectContaining({ textValue: 'test' }),
+      proxy: undefined,
+      state: { groupCounter: 1 }
+    },
+    '(?:test)': {
+      label: '',
+      regexp: jasmine.objectContaining({ textValue: 'test' }),
+      proxy: jasmine.objectContaining({ textValue: 'test' }),
+      state: { groupCounter: 1 }
+    }
+  }, (content, str) => {
+    it(`parses "${str}" as a Subexp`, function() {
+      var parser = new javascript.Parser(str);
+      expect(parser.__consume__subexp()).toEqual(jasmine.objectContaining(content));
+    });
+  });
+
+  describe('_anchor property', function() {
+
+    it('applies the local transform matrix to the anchor from the regexp', function() {
+      var node = new javascript.Parser('(test)').__consume__subexp();
+
+      node.regexp = {
+        anchor: {
+          ax: 10,
+          ax2: 15,
+          ay: 20
+        }
+      };
+
+      spyOn(node, 'transform').and.returnValue({
+        localMatrix: Snap.matrix().translate(3, 8)
+      });
+
+      expect(node._anchor).toEqual({
+        ax: 13,
+        ax2: 18,
+        ay: 28
+      });
+    });
+
+  });
+
+  describe('#_render', function() {
+
+    beforeEach(function() {
+      this.renderDeferred = Q.defer();
+
+      this.node = new javascript.Parser('(test)').__consume__subexp();
+      this.node.label = 'example label';
+      this.node.regexp = jasmine.createSpyObj('regexp', ['render']);
+      this.node.container = jasmine.createSpyObj('container', ['addClass', 'group']);
+
+      this.node.regexp.render.and.returnValue(this.renderDeferred.promise);
+    });
+
+    it('renders the regexp', function() {
+      this.node._render();
+      expect(this.node.regexp.render).toHaveBeenCalled();
+    });
+
+    it('renders a labeled box', function(done) {
+      spyOn(this.node, 'renderLabeledBox');
+      this.renderDeferred.resolve();
+      this.node._render()
+        .then(() => {
+          expect(this.node.renderLabeledBox).toHaveBeenCalledWith('example label', this.node.regexp, { padding: 10 });
+        })
+        .finally(done)
+        .done();
+    });
+
+  });
+
+});
diff --git a/src/js/parser/javascript/subexp.js b/src/js/parser/javascript/subexp.js
index 00f4692..8e4a56a 100644
--- a/src/js/parser/javascript/subexp.js
+++ b/src/js/parser/javascript/subexp.js
@@ -26,9 +26,11 @@ export default {
 
   _render() {
     return this.regexp.render(this.container.group())
-      .then(this.renderLabeledBox.bind(this, this.label, this.regexp, {
-        padding: 10
-      }));
+      .then(() => {
+        return this.renderLabeledBox(this.label, this.regexp, {
+          padding: 10
+        });
+      });
   },
 
   setup() {