Do you have all of Bootstrap 5 properly loading in the theme? Check your JavaScript includes and make sure the features you are trying to use are turned on and being compiled into your theme's "dist" files or whatever. In a lot of projects, many of the JS features (Popover, Dropdown, Tooltip, Carousel, etc.) are either not on by default or the theme creator disabled them.

If the above is not the problem, it could be that something is causing multiple Bootstrap versions to load. Check your page source and see if something is putting both Bootstrap 5 and Bootstrap 3 on the page. 

Also, if I am missing the boat with these guesses, please provide some more details, context, and specifics. It seems unlikely that DDRMenu is the problem and much more likely that the problem is on the front-end, HTML/CSS/JS and some needed CSS or JS is missing. 

Any DevTools console logged errors going on related to clicking your dropdowns?

Hey Jeremy,
Thanks for your reply. After reading your reply, I'm thinking it may be time to do some house cleaning. I've downloaded the latest dnn install file and I was expecting to find some skins in Portals\_default\Skins folder, but the only folder in there is another _default folder - no themes. Do you no if the themes are created during the install - which I haven't done yet.

In case someone else is searching for themes that come with the latest fresh install, Aperture is it. (7-28-26 DNN 10.03.02)

For those interested.. Xcillion-B5 DNN theme - Bootstrap 5 is in development

Posted By Jeff Frick on 7/28/2026 4:49 PM

For those interested.. Xcillion-B5 DNN theme - Bootstrap 5 is in development

OK I was not going to publish but, yes I will publish a BS 5 version of Xcillion.
But do not use it yet as I will re-do the menu.

Sounds Great! Thanks Timo!

I don't know if this is related to the beta version just released, but I received this error:
Could not load file or assembly 'System.Collections.Immutable' or one of its dependencies.
Other than that, the theme seems to be working great except for my own home page modules, which I'm modifying to see if they are the problem .
 

The issue comes down to a breaking change in Bootstrap 5's JavaScript API rather than DDRMenu itself.

BS5 changed data attributes from data-toggle="dropdown" to data-bs-toggle="dropdown" (along with data-bs-target, etc.). Because Xcillion’s built-in DDRMenu template still renders legacy BS3/BS4 data attributes, Bootstrap 5's JS simply ignores them and won't toggle the classes.

To fix it in your custom theme: W

Open your DDRMenu XSLT or Razor template (usually located in your theme folder under ULXSLT or similar).

Update the parent or tags so attributes use the data-bs-* prefix (e.g., data-bs-toggle="dropdown").

Ensure your theme layout imports bootstrap.bundle.min.js (which includes Popper.js) so the dropdown event listeners actually fire.

Thanks for your reply. I can't remember what I did to get rid of the error, but it's gone.