Hi @akku!
Could it be the “Bootstrap’s JavaScript requires jQuery version 1.9.1 or higher, but lower than version 3” javascript error? (from the browser console).
It seems that the <li class="dropdown"> that refers to the parent navigation menu item does not get the open class when the navigation menu item is being clicked. (at the image bellow the open class is added manually)
@NateWr correct me if I am wrong: @akku could you try that fix [Bootstrap3 ver 3.1.2 Error with OJS 3.1.2 loading jQuery 3.3.1 · Issue #114 · NateWr/bootstrap3 · GitHub] to see if it would help with your issue?
Thanks!
@Dimitris_Efstathiou