Hey David, Thank you! Sorry for my late reply.
I have thought again and I think mega menu is very complicated to style with GP. I also want to show menu descriptions etc…
Since my site is in diff languages, I already have 1 menu/lang. I can’t also do that for the slide off panel.
I hope soon GP/GB will enable us to build mega menu simply using elements and blocks. If you check now most of the websites on internet have a mega menu.
Thank you again.