I only seem to have this feature on my iPhone only. It's nowhere to be found on my iPad.
I think the iPad requests the desktop site already. You can tell that Facebook on iPhone requests their mobile site, and on iPad it requests the desktop site automatically.
I think that's more to do with how their website was coded, so it's at the discretion of the website as to how they want their website to be displayed to a particular device/user agent. I'm guessing Facebook have chosen to display their full website for iPad users rather than the iPad actively requesting full desktop access. Correct me if i'm wrong though, I might be wrong.
Scroll down when you are looking at your favorites.
So it only works if you have favorites??? I dont normally use favorites but added one to get this working. I enabled it and deleted favorite and it seems to be working.
You don't need favorites. You just need to tap into the smart search field. I was just saying that as it was easier to type.