Fixing bug in guisupport.py

IPython/lib/guisupport.py

@@ -110,13 +110,15 b' def get_app_qt4(*args, **kwargs):'
     from PyQt4 import QtGui
     app = QtGui.QApplication.instance()
     if app is None:
+        if not args:
+            args = ([''],)
         app = QtGui.QApplication(*args, **kwargs)
     return app
 
 def is_event_loop_running_qt4(app=None):
     """Is the qt4 event loop running."""
     if app is None:
-        app = get_app_qt4()
+        app = get_app_qt4([''])
     if hasattr(app, '_in_event_loop'):
         return app._in_event_loop
     else:
@@ -126,7 +128,7 b' def is_event_loop_running_qt4(app=None):'
 def start_event_loop_qt4(app=None):
     """Start the qt4 event loop in a consistent manner."""
     if app is None:
-        app = get_app_qt4()
+        app = get_app_qt4([''])
     if not is_event_loop_running_qt4(app):
         app._in_event_loop = True
         app.exec_()