text: Title: Can't copy paste content from the doc itself
  Body: ## Bug Report
  
  **Problematic behavior**
  I can't copy paste content from the doc I'm working on.
  When I copy paste from outside the docs it works
  
  **Steps to Reproduce**
  1. Select content on the doc
  2. Ctrl + C
  3. Ctrl + V 
  4. Nothing happens
  
  **Environment**
  docs.numerique.gouv.fr on firefox
  - Impress version:
  - Platform:
  
  **Possible Solution**
  <!--- Only if you have suggestions on a fix for the bug -->
  
  **Additional context/Screenshots**
  Add any other context about the problem here. If applicable, add screenshots to help explain.
  