The weakest point I've seen in these kind of new LiveScript forums is the new scrollbar. On my mobile it is terrible. I tried the other popular forum not long ago, although I don't remember the name, something with a D.... When you used the new scrollbar to get to posts, it was utter terrible, now it was getting the Posts as well and Flarum does not do that which might be the reason maybe that Flarum is quicker and much more smooth yet still not totally satisfying for sure but absolutely more workable. So I would suggest the programmers to have an eye on this weak point - I don't know if there is a reason why you don't have a preview of posts, but I'm afraid it might make it an utter horrible experience. So, whatever you can do to smooth this out so it is working smoothly on mobile - would be thumbs up.
I've tried 2 of these new Forums and the weakness of this new scrollbar was seen in both of them on my mobile. And That's all 🙂
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Not sure why Performance is not the main subject, I thought I took that as the main.... Whatever...
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When I try to edit the tags it jumps up and then nothing.... So can't do anything with the tags. But Performance was the primary thing I was thinking about.