OK – I think I made a little progress. There’s a Max Mega Menu setting “Active Menu Instances” and I had that set to 1. I had changed it while trying to troubleshoot. I’ve returned it to “0” – which is the default and applies MMM to all menus. I’m getting the mega menu to show up now. However, it’s on the left side of the top nav similar to Jonathan above. When I try to use his solution of applying an order CSS rule to #mega-menu-wrap-primary it has some unwanted side affect. I tried using the value of 4 since I believe that’s what the GP default “primary-nav” div gets when MMM is disabled. While it does place the mega menu on the right, when the browser is resized, there’s some weird padding or something happening on the right side of the screen and content slides around. Also, GP’s sticky header breaks whenever I add any order rule to the MMM wrapper div.