diff --git a/demo/cabaret.py b/demo/cabaret.py
index 1353b4e..b7e746a 100755
--- a/demo/cabaret.py
+++ b/demo/cabaret.py
@@ -50,5 +50,11 @@ else:
     wsreload.monkey_patch_http_server({'url': url}, callback=log)
     app.logger.debug('HTTPServer monkey patched for url %s' % url)
 
+try:
+    import wdb
+except ImportError:
+    pass
+else:
+    app.wsgi_app = wdb.Wdb(app.wsgi_app, start_disabled=True)
 
 app.run(debug=True, threaded=True, host='0.0.0.0', port=12221)
diff --git a/pygal/config.py b/pygal/config.py
index 9a6343f..f461cf4 100644
--- a/pygal/config.py
+++ b/pygal/config.py
@@ -143,12 +143,12 @@ class Config(object):
     x_labels_major = Key(
         None, list, "Label",
         "X labels that will be marked major.",
-        str)
+        subtype=str)
 
     x_labels_major_every = Key(
         None, int, "Label",
         "Mark every n-th x label as major.")
-    
+
     x_labels_major_count = Key(
         None, int, "Label",
         "Mark n evenly distributed labels as major.")
@@ -209,7 +209,7 @@ class Config(object):
         "No data", str, "Text", "Text to display when no data is given")
 
     label_font_size = Key(10, int, "Text", "Label font size")
-    
+
     major_label_font_size = Key(10, int, "Text", "Major label font size")
 
     value_font_size = Key(8, int, "Text", "Value font size")