title: Plotly express is not rendered in jupyter lab
body: <p>The following code does not render in Jupyter lab:</p>
  
  <pre><code>%matplotlib widget
  import plotly.express as px  
  import numpy as np 
  import pandas as pd
  
  df = pd.DataFrame(np.random.randint(0,100,size=(5, 4)), columns=list('ABCD'))
  px.bar(df, x='A', y='B')
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/qf4wK.png" rel="noreferrer"><img src="https://i.stack.imgur.com/qf4wK.png" alt="enter image description here"></a>
  I have tried to install all the dependencies and extensions mentioned in here
  <a href="https://plot.ly/python/getting-started/#jupyterlab-support-python-35" rel="noreferrer">https://plot.ly/python/getting-started/#jupyterlab-support-python-35</a> </p>
  
  <p>but also the steps in here 
  <a href="https://github.com/matplotlib/jupyter-matplotlib" rel="noreferrer">https://github.com/matplotlib/jupyter-matplotlib</a></p>
  
  <p>Nothing worked</p>
  
  <p>Here is my set up:</p>
  
  <pre><code>jupyter lab --version
  1.0.2
  
  python --version
  Python 3.6.1 :: Continuum Analytics, Inc.
  
  conda list jupyterlab
  # packages in environment at C:\Users\***\Anaconda3:
  #
  # Name                    Version                   Build  Channel
  jupyterlab                1.0.2            py36hf63ae98_0
  jupyterlab_launcher       0.13.1                   py36_0
  jupyterlab_server         1.0.0                      py_0
  
  conda list nodejs
  # packages in environment at C:\Users\***\Anaconda3:
  #
  # Name                    Version                   Build  Channel
  nodejs                    0.1.1                    pypi_0    pypi
  
  conda list plotly
  # packages in environment at C:\Users\***\Anaconda3:
  #
  # Name                    Version                   Build  Channel
  plotly                    4.1.0                    pypi_0    pypi
  plotly-express            0.4.1                    pypi_0    pypi
  </code></pre>
  
  <p>EDIT:</p>
  
  <pre><code>jupyter-labextension list
  JupyterLab v1.0.2
  Known labextensions:
     app dir: C:\Users\***\Anaconda3\share\jupyter\lab
          @jupyter-widgets/jupyterlab-manager v1.0.2 enabled  ok
          @jupyterlab/git v0.8.0 enabled  ok
          @jupyterlab/plotly-extension v1.0.0 enabled  ok
          jupyter-matplotlib v0.4.2 enabled  ok
          jupyterlab-chart-editor v1.2.0 enabled  ok
          jupyterlab-plotly v1.1.0 enabled  ok
          plotlywidget v1.1.0 enabled  ok
  </code></pre>