Using the blank JA 4 bootstrap template.
I had the problem that I could use Bootstrap 5 tabs in an article. They worked correctly.
But then, when I added them to a custom module (for use on my frontpage) they did not work.
Searching I found this issue : https://www.joomlart.com/forums/d/41068-tabs-addon-not-working-on-a-page-or-in-custom-module/32
It seems that the JS file for tabs was not being loaded when I use tabs in a custom module.
I can manually include this JS file (tab.min.js) in my module. But it would be good if this was enabled when using tabs in a module.
D.