Fresh install of Joomla 4 with the Cassiopeia template and I just set the menu module layout to collapsible Dropdown.

Now the hamburger menu is there for mobile and it will expand but not close? It adds the class "collasping" but then immediately reverts to "collapse show". So looks like its not removing the "show" class.

This is the same if I set it as Default collapsible too. Any ideas?

  • 3
    I have a fresh install and i do not see this problem on cassiopeia hamburger menu. It works without any problem. Have you loaded any custom JS file on the template? Do you see any console error?
    – Zollie
    Mar 8, 2023 at 17:09
  • 1
    Yes it was due to a custom JS file! I was trying to load the bootstrap JS twice. My mistake here.
    – j00m
    Mar 10, 2023 at 15:51
  • @j00m if your question is answered or your issue has been resolved please leave an answer for your question and be sure to close it out so we can keep the JSE free of orphaned questions.
    – Terry Carter
    Mar 13, 2023 at 18:07

1 Answer 1


I had included the Bootstrap dist JS file not realising and it was messing with this functionality. I removed the line and all was well.

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