title: Unhide all cells in Google Colab
body: <p>Is there a way to unhide all hidden cells in a Jupyter notebook on Google Colab?</p>
  
  <p>It appears that google colab hides cells automatically.  Is there a way to unhide all cells?  It's a pain to click each hidden cell especially when they are nested.  And I sometimes inadvertently skip over hidden cells when reviewing a notebook.</p>