**Fix:** Use div instead of button to handle old firefox versions

[fabien0102]

Summary

On firefox 60 (yeah, I know…), having a clickable element inside a <button /> is not working. Using a div instead solve this problem.

To be tested

Me

• [x] No error or warning in the console on localhost:6060
• [x] Try the tab on firefox 60, I can click on an icon inside a tab (close button)

Tester 1

• [x] See if the tabs are still working as before