Hello kas1983
You can see here https://forum.lauyan.com/d/1177-mega-menu/3
I might have a temporary workaround while we wait for Lauyan to chime in.
In the HEAD of Options -> Security & HTML, you can add this little script.
However, you have to publish to see the effect.
<style>
.dropdown-content{
width: 80vw;
}
</style>
You can adjust the width value to suit your site. With 80, it looks like this at full screen width.
Cordially
frangin62
