Striking

Striking integrates with UberMenu very well, but because the header elements of striking are all positioned absolutely, you’ll need to position UberMenu absolutely with custom CSS as well.

#megaMenu{
  position: absolute;
  right: 0;  
  bottom: 0;
  width: 650px; /* Optional */
}

Also see this excellent tutorial: How to get Übermenu full width in striking

If you are using the Sticky Extension, you may need to add some code like this:

#megaMenu,
#megaMenu-sticky-wrapper{
 right: 0 !important; 
 bottom: 0 !important; 
 top:auto;
 left:auto;
 position: absolute !important; 
}
#megaMenu-sticky-wrapper{
 width:100%; 
}