diff --git a/src/lib/svg_text_utils.js b/src/lib/svg_text_utils.js
index 3100c222170..37d8de07458 100644
--- a/src/lib/svg_text_utils.js
+++ b/src/lib/svg_text_utils.js
@@ -114,10 +114,11 @@ exports.convertToTspans = function(_context, gd, _callback) {
                 .style({overflow: 'visible', 'pointer-events': 'none'});
 
                 var fill = _context.node().style.fill || 'black';
-                newSvg.select('g').attr({fill: fill, stroke: fill});
+                var g = newSvg.select('g');
+                g.attr({fill: fill, stroke: fill});
 
-                var newSvgW = getSize(newSvg, 'width');
-                var newSvgH = getSize(newSvg, 'height');
+                var newSvgW = getSize(g, 'width');
+                var newSvgH = getSize(g, 'height');
                 var newX = +_context.attr('x') - newSvgW *
                     {start: 0, middle: 0.5, end: 1}[_context.attr('text-anchor') || 'start'];
                 // font baseline is about 1/4 fontSize below centerline
diff --git a/tasks/test_bundle.js b/tasks/test_bundle.js
index e561e05b3dd..ffa394cc408 100644
--- a/tasks/test_bundle.js
+++ b/tasks/test_bundle.js
@@ -31,6 +31,23 @@ glob(pathToJasmineBundleTests + '/*.js', function(err, files) {
         };
     });
 
+    var mathjaxTestFirefox = function(cb) {
+        var cmd = [
+            'karma', 'start',
+            path.join(constants.pathToRoot, 'test', 'jasmine', 'karma.conf.js'),
+            '--FF',
+            '--bundleTest=mathjax',
+            '--nowatch'
+        ].join(' ');
+
+        console.log('Running: ' + cmd);
+
+        exec(cmd, function(err) {
+            cb(null, err);
+        }).stdout.pipe(process.stdout);
+    };
+    tasks.push(mathjaxTestFirefox);
+
     runSeries(tasks, function(err, results) {
         if(err) throw err;