GLXBadDrawable when using multiple QVTKRenderWindow in a QMdiArea

vtk_baddrawable.py

#!/usr/bin/python

import sys

import vtk
from vtk.qt4.QVTKRenderWindowInteractor import *

from PySide.QtCore import *
from PySide.QtGui import *

if __name__ == '__main__':
    #Qt boilerplate
    app = QApplication(sys.argv)
    main_window = QMainWindow()
    main_layout = QHBoxLayout()
    mdi_area = QMdiArea(main_window)

    #VTK will render on those frames
    qframe1 = QFrame()
    qframe2 = QFrame()

    qhbox1 = QHBoxLayout()
    qhbox2 = QHBoxLayout()

    #Our two Qt VTK RenderWindowInteractor
    vtk_interactor1 = QVTKRenderWindowInteractor(parent=qframe1)
    vtk_interactor2 = QVTKRenderWindowInteractor(parent=qframe2)

    #Each subwindow possess its own VTK interactor
    qhbox1.addWidget(vtk_interactor1)
    qframe1.setLayout(qhbox1)
    mdi_area.addSubWindow(qframe1)

    qhbox2.addWidget(vtk_interactor2)
    qframe2.setLayout(qhbox2)
    mdi_area.addSubWindow(qframe2)

    #Make the MDI area the central widget
    main_window.setCentralWidget(QWidget())
    main_window.centralWidget().setLayout(main_layout)
    main_layout.addWidget(mdi_area)

    #Create our VTK renderer
    ren1 = vtk.vtkRenderer()
    vtk_interactor1.GetRenderWindow().AddRenderer(ren1)
    ren2 = vtk.vtkRenderer()
    vtk_interactor2.GetRenderWindow().AddRenderer(ren2)

    #A cone source
    cone = vtk.vtkConeSource()
    cone.SetResolution(8)

    coneMapper = vtk.vtkPolyDataMapper()
    coneMapper.SetInputConnection(cone.GetOutputPort())

    coneActor = vtk.vtkActor()
    coneActor.SetMapper(coneMapper)

    #Each renderer will display a cone
    ren1.AddActor(coneActor)
    ren2.AddActor(coneActor)

    #Render our cone
    vtk_interactor1.GetRenderWindow().Render()
    vtk_interactor2.GetRenderWindow().Render()

    main_window.show()

    app.exec_()